Ever wondered just how effective a first serve is over a second serve?

The answer is right around 40 per cent better on average, and surprisingly, it has changed very little in the past quarter of a century in our sport.

A 26-season study of first-and-second serve-win percentages from 1991 to 2016 uncovered that time and technology have had very little influence on the performance of what is widely regarded as the most dominant shot in a match.

Tennis discussions often focus on how athletes are getting faster, racquets are getting more powerful, and strings let players manipulate the ball like it’s on a Yo-Yo. These factors all seem to be true on the surface, but somehow fail to significantly move the needle when you look at raw serve analytics.

An Infosys ATP Beyond The Numbers analysis of the Top 50 performers in first and second serve points won every season from 1991 to 2016 uncovers an average 43 per cent improvement in first serve points won over second serve points won. Since 2000, the average has been slightly less at 41 per cent.

World No. 1 Andy Murray averaged winning 76 per cent of his first serve points in 2016, and 54 per cent on second serves. That created a 41 per cent advantage for his first-serve win percentage over his second serve – exactly the same as the larger 2016 sample size.

Top 50 Performers 1991-2016: 1st & 2nd Serve Wins Percentage / Percentage Difference

Top 50 – 1st Serve Points Won Average (75%)
The ATP Stats LEADERBOARDS, powered by the Infosys Information Platform, show that the Top 50 performers in first-serve points won each season has hardly changed at all over the past 20 years, dating back to 1997. The average has either been 73 per cent, 74 per cent or 75 per cent. The highest season was 1996 at 76 per cent, which was the only time it reached that level since 1991.

Top 50 – 2nd Serve Points Won Average (52%)
There has also been remarkable consistency in average second-serve points won as well, producing an average of 52 per cent points won, while deviating just four data points from 50 per cent to 53 per cent. For the past 14 straight seasons, from 2003 to 2016, the points won average of the leading 50 players in this specific service category has been 53 per cent each year.

Top 50 – Percentage Difference (43%)
The average difference in points won of 43 per cent was bumped all the way up 50 per cent in 1997. The mid-1990s in general were the most dominant serving era in our sport, with players such as Pete Sampras, Richard Krajicek, Goran Ivanisevic, Greg Rusedski and Boris Becker leading the way.

At the recently completed 2017 Australian Open, players averaged making 61 per cent of their first serves for the tournament. Tennis in so many ways is a numbers game. Knowing how many first serves typically go in, what their return investment is, and the corresponding win percentage with second serves helps us better organise the sport in our minds. And also allows us to know exactly what to expect in a match.

It’s almost as if Borna Coric has hit the reset button on his young career to start the 2017 ATP World Tour season. The 20-year-old Croatian is working with a new coach. He has changed racquet brands. The right-hander has his health back as well, following surgery on his right knee late last season.

It should all add up to an improved year for the Zagreb native, who had to cut short his 2016 campaign because of the knee surgery in early September. Physicians removed two small pieces of bone that had broken off and lodged inside a tendon in his right knee, Coric said.

He sat out from tennis for about two months, taking the court again on 10 December. But it’s been a slow recovery for the #NextGenATP player. Coric experienced pain in his shoulder and hip, and he underwent more rehab after his first-round loss to Alexandr Dolgopolov at the Australian Open last month.

“It was a tough comeback but now I’m more or less fine,” he told ATPWorldTour.com in Delray Beach.

You might expect a 20-year-old who’s already achieved impressive results – last year, at 19 years, 9 months, he became the youngest ATP World Tour Masters 1000 quarter-finalist since Novak Djokovic in 2006 – to be expecting instant results for his new-look 2017. But Coric, who was closing in on the Top 30 before his surgery, is approaching the season with the mindset of an ATP World Tour veteran.

“I have changed many things in my game… So I need some time to adapt,” he said.

Of the various changes, Borna Coric is perhaps most enthused about his coach, Ivica Ancic, whom Coric has known since he was 12. Ancic is the older brother and former coach of Mario Ancic, who reached No. 7 in the Emirates ATP Rankings and won three ATP World Tour titles but had to retire in 2011 because of health problems, including complications from mononucleosis.

Coric split with former coach Miles Maclagan in September, and he took seriously the task of finding a new coach. He had two phone conversations with Ancic and met with him one-on-one on two other occasions, chatting with Ancic for two hours each time.

“I think it’s important to meet the person who you’re going to travel with maybe the rest of your [career],” Coric said. “Obviously I felt like we’re going to click.”

The young Croatian has experienced a few coaching changes since turning pro in 2013. He has worked with Zeljko Krajan and Thomas Johansson. The changes haven’t been all bad, though. By working with different experts, Coric said, he’s learned about himself and what works for him on the court.

He’s looking forward to stability with Ancic. “It’s tough to change every six months because obviously every coach has maybe a different view on how you need to play and a different mentality,” Coric said.

He and Ancic are in agreement on the way forward for the right-hander who was on the cusp of winning his first ATP World Tour title twice last season. In January, Coric lost in the Aircel Chennai Open to Stan Wawrinka. Three months later, he fell to Federico Delbonis on the clay in Marrakech.

“I need to be more aggressive obviously than I was but then at the same point, I need to be careful to not be too aggressive,” Coric said. “If you only practise on attacking, you’re going to lose some part of your game, which is the defense, which is the best part of my game. So I need to be careful not to lose what I’m best at.

Read More: Six Things To Know About Norway’s Ruud

“That’s the balance you need to find, which comes with matches, which obviously I’m trying to find now.”

He has found his rhythm at the Delray Beach Open, where Coric is making his debut. The Croatian breezed past Colombia’s Santiago Giraldo 6-2, 6-3, needing only 68 minutes to advance into the second round, where he’ll face top seed Milos Raonic. Coric feasted on Giraldo’s second serve, winning 71 per cent of those points (15/21).

Coric, No. 59 in the Emirates ATP Rankings, has never faced Raonic, who, at No. 4, is the highest-ranked player to participate in the Delray Beach tournament during its 25-year history. Win or lose, though, the Croatian is focused on the end game, what he hopes will be a long career on the ATP World Tour.

“That’s like with everything in life… There are ups and downs, obviously. I started playing better during the [U.S.] summer last year, then I got injured, which was unlucky. I was ranked maybe No. 40 and I didn’t have to defend almost any points. So I could have finished in the Top 30 maybe,” Coric said. “That’s tennis – ups and downs. Now starting the year I haven’t played for four months. I knew it was going to be tough to start. You just need to work your way up.”

#NextGenATP player Casper Ruud has caused a stir at the Rio Open, where he defeated Rogerio Dutra Silva to claim his first ATP World Tour win. Ahead of his second-round contest with Roberto Carballes Baena, we present the need-to-know on the 18-year-old Norwegian.

1. Tennis Is In His DNA
His father, Christian Ruud, was a Top 50 professional tennis player. He reached his career-high No. 39 in the Emirates ATP Rankings on 9 October 1995, and finished his career with 115 tour-level victories.

“I have a great relationship with my father,” said Ruud. “Sometimes in the world of sport it isn’t easy to have such a strong relationship, but for us it’s marvellous.

“We are both very competitive and both love to win at everything. We do it with the greatest respect and it’s a healthy rivalry. He is an essential part of my team. I don’t feel any pressure that he was a professional player. In fact, it’s the opposite; it has helped me a lot.”

2. He Scored His First ATP Win At A 500 Tournament
His first victory came in his third ATP World Tour tournament. “It’s been great,” said Ruud. “Not just winning my first match, but having the chance to be here and playing in an ATP World Tour 500. I am the lowest-ranked player in the draw, so I’m the underdog in every match and that’s more comfortable for me. I’m trying to keep my feet on the ground and keep working hard.”

Yesterday I was in sorrow for missing out @theweeknd concert in Oslo but today made it all up, thanks Rio!!??????? @RioOpenOficial

— Casper Ruud (@CasperRuud98) February 21, 2017

3. He Is Already A Rising Star In Norway
“Norwegians really like to see young, home-grown talent making progress,” said Ruud. “We have Martin Odegaard, who plays for Real Madrid, as well as one of the best skiers in the world, and now they are starting to enjoy tennis. It’s great for the Federation and for us. If people enjoy following me, then that’s great!”

4. He’s On A Rapid Rise
After turning professional in 2015, Ruud is a player who has got the most out of every experience in all levels of professional tennis. He won his first ITF Futures in Paguera, Spain, in February 2016. In his first ATP Challenger Tour event in Seville, also last year, he came through qualifying and ended up winning the title (d. Daniel).

In one year, the teenager jumped from outside the Top 1,000 to the verge of the Top 200 and also secured the prestigious No. 1 mantle on the junior circuit.

5. His Coach Is Spanish
Pedro Rico has been Ruud’s coach for two years. With the Spaniard, Ruud has made rapid progress. The partnership gels perfectly between the passionate Spaniard and the cool and calm Scandinavian. “The phrase I hear the most in Team Casper is ‘No Stress’,” said Rico.

“Pedro is great,” said Ruud. “He is helping me so much to get better, and together we have already gone from outside the Top 1,000 to be the No. 1 junior and close to the Top 200.”

6. Milan Is His Goal For The Season
“For the young players, the Next Gen ATP Finals is the biggest event we can win,” said the 18-year-old Ruud. “It is a big motivation.

“Everyone wants to qualify and that means it won’t be easy. It’s too soon to think about it at the moment, but for me it would be a huge honour to participate.”

Tommy Haas didn’t miss that feeling.

The 38 year old, who’s embarking on his final comeback, led Georgian Nikoloz Basilashvili by a set and a break during their first-round match at the Delray Beach Open on Tuesday. But then Haas’ lack of recent match experience struck.

Leading 4-3 in the second set, Haas was broken and fell in the 18-point tie-break. Basilashvili cruised in the decider, breaking twice to move into the second round 6-7(4), 7-6(8), 6-2 and end Haas’ run in south Florida.

“Overall it was good,” Haas said. “It just sucks when you’re that close to possibly winning a match and you don’t win. I haven’t had that feeling in a long time… and it’s not a good feeling.”

It was Haas’ first complete singles match in 16 months, since October 2015, when he fell to Jo-Wilfried Tsonga at the Erste Bank Open 500 in Vienna. Haas played at the Australian Open last month but retired after two sets because of fatigue. He hasn’t won a tour-level singles contest since the 2015 Wimbledon.

“I’m just trying to find my game, just trying to go out there and compete and possibly play the game to a level that I feel comfortable at. But it’s so tough when you were out for over a year and you come back and you play like eight events and you’re out for over a year and now it’s your second time back,” Haas said. “So it’s tough for me to see where I’m at, and practice is always different.”

His body mostly held up against Basilashvili, who reached his second tour-level final on Sunday at the Memphis Open (l. to Harrison). Haas had a brief scare during the second set when he felt a tendon in his right quadricep tug on him.

“For a few steps there, up until I got to the sideline, I couldn’t really lift my leg. So I was thinking, ‘Please don’t let it be something too serious’,” Haas said. “It really felt weird. It didn’t really feel like a pop, it just felt like a little stinger.”

He received treatment on it, though, and finished the match without a recurrence.

Tuesday night will most likely be the last time fans see Haas play a singles match at the Delray Beach Tennis Center. The 15-time ATP World Tour titlist underwent foot surgery in April. He has said this latest comeback – his ninth during his 21-year career – will be his final. He’s already working his after-tennis job as the BNP Paribas Open tournament director in Indian Wells.

“I really enjoyed the match against him. I respect him a lot,” said Basilashvili, who had never faced Haas before Tuesday. “Of course for him it’s difficult to come back… It’s sad, of course that he did not go through, but that’s tennis and sports. But I wish him good luck the rest of the season.”

Haas is sticking around Delray Beach. He’s scheduled to play his quarter-finals match with Canadian Vasek Pospisil on Wednesday afternoon.

Read More: Raonic Shines On Delray Beach Debut

Juan Martin del Potro made a tentative, but ultimately successful, 2017 ATP World Tour debut Tuesday night at the Delray Beach Open, posting a 6-4, 6-4 win over Kevin Anderson. In a battle of the former Delray Beach champions, del Potro hit cautiously off his backhand wing and survived a tumble in the first set that left him with a grazed right knee.

The former US Open champion, who has endured three left wrist surgeries (in addition to 2010 surgery on his right wrist), struggled to generate pace on his backhand and mixed in a number of one-handed slices. When Anderson approached the net, del Potro elected to either lob or stretch the South African with well-placed, medium-paced backhands.

But the Argentine’s powerful serve and flat, thumping forehand were enough to steer him to a sixth win in six career FedEx ATP Head2Head meetings with the 6’ 8” Anderson.

“It’s not easy in my first match to show good tennis but I think I did well,” del Potro said. “I survived in the first game of my serve, and then I started to serve much better. I started to feel the ball better and better. And I think for the conditions tonight, we made a good tennis match and always the most important thing is when you don’t feel 100 per cent is trying to win the match and I did.”

 Watch Full Match Replays

Assessing his backhand, del Potro said, “I think I did well with my slices but I could improve my two-handed backhand a lot. For being my first match of the season, I think it’s okay, but I need to keep working hard and start to find the way to make winners with my backhand as well.”

Of his forehand, he said, “It was effective but I can hit it even better. I made some easy mistakes with my forehand but fortunately not in the important moments. But when I have the confidence on the forehands I can hit it cross-court or down the line; I can play whatever I like, and that’s happened only with my forehand, not with my backhand yet and that’s what I have to work on.”

Del Potro, 28, also began his 2016 season in Delray Beach, reaching the semi-finals. He went on to win 32 matches to finish inside the Top 40 of the Emirates ATP Rankings and to be named ATP Comeback Player of the Year for the second time.

Del Potro required just one break in each set. He converted his fifth break chance of the match for a 4-3 lead in the first set and seized his first break chance for a 2-1 lead in the second set.  The Tandil native next plays the man who beat Anderson last week in Memphis, Damir Dzumhur.

Anderson, the 2012 champion, dropped to 0-2 on the season, following an opening-round loss last week in Memphis. “He made me play a couple of balls in the games I got broken on, and I played some loose points and that basically decided that match,” Anderson said.

Home favourite Thomaz Bellucci received a standing ovation after dismissing Rio Open presented by Claro top seed Kei Nishikori 6-4, 6-3 on Tuesday.

Nishikori reached the Argentina Open final last week and won their only previous meeting on the clay at the 2015 Roland Garros in straight sets, but the top-ranked Brazilian put in a commanding display to defeat the World No. 5.

“Actually everything didn’t work well,” said Nishikori. “Probably the condition changed a lot from last week: bounce really high and the balls are really heavy. The ball is the most difficult to adjust. I couldn’t feel anything today. I think it wasn’t my day.”

Bellucci, quarter-finalist in 2014, earned a second-round encounter with countryman Thiago Monteiro. The World No. 85 defeated Gastao Elias 2-6, 7-6(4), 6-4.

 Watch Full Match Replays

World No. 8 Dominic Thiem made his way safely through his opening match, defeating former World No. 8 Janko Tipsarevic 6-4, 7-5. The second seed, a semi-finalist last year on his tournament debut, capitalised on three of his five break points en route to the one hour, 35-minute victory. Thiem next faces another Serbian, Dusan Lajovic, as he looks to reach his fourth quarter-final of 2017.

Alexandr Dolgopolov maintained his title-winning form from Buenos Aires last week with a 6-4, 6-4 victory over 2015 champion David Ferrer. Sixth seed Ferrer led their FedEx ATP Head2Head 9-3, however, Dolgopolov managed to repeat his 2014 win in Rio over the Spaniard to advance into the second round.

Two other Spanish seeds avoided the fate of their countryman. Fourth seed Pablo Carreno Busta ousted Brazilian wild card Joao Souza 6-3, 6-2, while fifth seed Albert Ramos-Vinolas beat Stephane Robert 6-2, 6-0. Carreno Busta goes on to face recent Quito champion Victor Estrella Burgos, a 6-2, 7-5 winner over 2016 Rio finalist Guido Pella. Ramos-Vinolas will take on Fabio Fognini, who defeated veteran Spaniard Tommy Robredo 6-2, 6-4 to avenge a straight-sets loss in Buenos Aires.

Argentine Federico Delbonis improved to a 4-0 FedEx Head2Head record against Italian Paolo Lorenzi as he rallied for a 4-6, 6-1, 6-4 win in two hours and 13 minutes.