Novak Djokovic has had an easy passage to the US Open fourth round… perhaps a little too easy. The top seed was leading 4-2 in Friday’s third-round meeting with Mikhail Youzhny when the Russian retired with a leg injury.

Having received a walkover from Czech Jiri Vesely in the second round, Djokovic’s biggest concern heading into the second week of the Open will be a lack of match play. Top of mind will be the walkover Djokovic received from Fabio Fognini in the Roland Garros quarter-finals in 2011. At the time Djokovic was on a 43-match winning streak but the disruption to his rhythm caused by the Fognini walkover was attributed in part to his stumble against Roger Federer in the semi-finals.

Djokovic will meet the winner of John Isner and Kyle Edmund in the fourth round.

Jack Sock has come a long way from finding himself in a five-set battle with Taylor Fritz in the first round on Monday. Four days later and the American is through to the US Open fourth round for the first time after upsetting seventh seed and former champion Marin Cilic 6-4, 6-3, 6-3.

The 26^th-seeded Sock, who had fallen in the third round twice before, dominated proceedings, winning 28 points more than Cilic and limiting himself to just 15 unforced errors as he prevailed in one hour and 41 minutes.

Sock recorded his first Top 10 win in a major to reach the last 16 at a Grand Slam for the second time, having also done so at Roland Garros last year (l. to Nadal). Looking to reach his first Grand Slam quarter-final, Sock will face Jo-Wilfried Tsonga.

The 23-year-old Sock is coming off a memorable summer, which saw him clinch a mixed doubles gold medal at the Olympics, alongside Bethanie Mattek-Sands, and bronze in the men’s doubles with Steve Johnson. He was also a quarter-finalist at the Citi Open (l. to Karlovic) and reached the third round in Toronto (l. to Wawrinka). Earlier in the year, the Kansas resident was runner-up in Auckland and Houston.

Cilic was looking for a repeat of his 2014 title-winning run at Flushing Meadows. The Croat, who is playing his first tournament with new coach Jonas Bjorkman, came into the US Open in top form, after winning his first ATP World Tour Masters 1000 title in Cincinnati, where he defeated Andy Murray in the final.

Ninth seed Jo-Wilfried Tsonga showcased a new boxing-style celebration as he sealed his place in the fourth round of the US Open on Friday. The Frenchman, oft-likened in appearance to the late Muhammed Ali, defeated Kevin Anderson 6-3, 6-4, 7-6(4) before showcasing his shadow boxing moves on Grandstand.

The 31-year-old Tsonga avoided a fourth set as he fended off a set point in a lengthy 10^th game of the third set, before edging Anderson in the ensuing tie-break to claim victory in two hours and 50 minutes.

“It’s never easy to play that kind of player,” said Tsonga. “He’s serving well. He’s also moving well from his baseline for his height. Today it was a good challenge for me to beat him. I did it well. It was a good match for me.”

A good run at the US Open could see Tsonga mount a late charge in the Emirates ATP Race To London. He is currently 16^th, more than 1000 points behind eighth-placed Gael Monfils. Injuries have blighted parts of his season, but the right-hander came back strongly at Wimbledon, where he reached the quarter-finals (l. to Murray).

As he looks to reach the US Open quarter-finals for the third time, Tsonga will face Jack Sock. The Frenchman reached the last eight in 2011 (l. to Federer) and 2015 (l. to Cilic).

No. 10 seed Monfils surged into the second week with a confident 6-4, 6-2, 6-4 win over Nicolas Almagro in the third round. After cruising to a two-set lead, Monfils emerged the winner by taking an unusual third set which featured five consecutive breaks of serve.

The Frenchman only dropped six first-serve points in the one-hour, 49-minute victory and broke Almagro seven times to even his FedEx ATP Head2Head rivalry at 3-3. The explosive Monfils stayed within his comfort zone against the hard-hitting Spaniard, firing 31 winners and only 20 unforced errors. Meanwhile, Almagro hit 18 winners and succumbed after making 42 unforced errors.

In the fourth round, the 2010 and 2014 US Open quarter-finalist will take on Marcos Baghdatis. The Cypriot’s lone victory against Monfils came a decade ago at the ATP World Tour Masters 1000 event in Cincinnati.

Rising French star Lucas Pouille is into the second week in New York after outlasting Spanish veteran Roberto Bautista Agut 3-6, 7-5, 2-6, 7-5, 6-1. The 22 year old, who reached his first Grand Slam quarter-final at Wimbledon this year, is into the fourth round of a major tournament for the second time. The No. 24 seed broke serve in the final game of a tight fourth set, then raced to a 5-0 lead in the final set against Bautista Agut. He finished with 67 winners, including 14 aces.

You don’t want to go the distance with Kei Nishikori. When matches get extended to deciding sets, Nishikori is the most successful player of all time winning them. This speaks to how well his physical game holds up under pressure, and how strong his mind is to not buckle with both players in the match so close to the finish line. 

A FedEx ATP Performance Zone analysis reveals that Nishikori takes a 50-50 battle at the start of a deciding set and wins almost eight out ten of them. In a one-set shootout to decide the final outcome, Nishikori’s will to win and ability to craft a winning game plan helps him find another gear to elevate himself above the pack.

The career Top 10 list is this category is a mixture of playing styles from different eras, indicating that success in this area is not predicated on specific physical attributes, but rather mental and emotional toughness under pressure.

View Career Performances In Deciding Sets 

Interestingly, every player in the Top 10 Career Deciding Sets Won index has been ranked in the Top 4 of the Emirates ATP Rankings, with seven of them former World No. 1s.

The FedEx ATP Performance Zone win-loss index also uncovered several other former World No. 1s in the 10-20 range, including Boris Becker (12), John Newcombe (13) Thomas Muster (14), Mats Wilander (15), Yevgeny Kafelnikov (19) and Ivan Lendl (20).

In 2016, Nishikori is continuing his outstanding performance in deciding sets, going 11-3, placing him in sixth place this season with a 78.6 win percentage. The five players in front so far in 2016 are Dominic Thiem (95 per cent / 19-1), Novak Djokovic (85.7 per cent / 6-1), Milos Raonic (84.6 per cent / 11-2), Tomas Berdych (80 per cent / 8-2) and John Millman (80 per cent / 8-2).

In the past 52 weeks, Thiem has won the most deciding set matches with 21, with Murray a close second with 18 wins, and Nishikori tied for third place with Benoit Paire and Nadal with 16 victories.

Third seed Stan Wawrinka looked like a man on a mission in his second round dismissal of qualifier Alessandro Giannessi, downing the Italian 6-1, 7-6(4), 7-5 at the US Open.

Wawrinka, a semi-finalist in two of the past three years in Flushing Meadows, has not dropped a set en route to the third round. The Swiss completed the victory in two hours and 28 minutes, striking 57 winners, while turning aside 10 of 11 break points faced.

“It’s always better to win in three sets, that’s for sure,” said Wawrinka. “But I was ready to go even longer in that court. It was not as hot as the other day, but it was really humid. I think except for that little moment when I got broken in the second, there were a few games when I was a little bit out of it mentally and not as focused as I wanted. But I came back. In general, I think it was a great level.”

Giannessi capped an impressive run through qualifying, which saw him reach his first Grand Slam main draw, and claim his first tour-level match win in more than four years. Wawrinka admits the World No. 243 gave him a stern test.

“I never played against him, but I watched him before,” Wawrinka said of Giannessi. “I talked with [coach] Magnus [Norman] and knew what to expect. He is a great player. He has some great shots. He’s feeling the ball well. It was a tough match, as I expected. But I think I’m quite happy to have won in three sets.”

Wawrinka now awaits resurgent Brit Daniel Evans, who continued his strong run of form with a 6-4, 6-4, 5-7, 6-2 upset of 19-year-old and 27th seed Alexander Zverev. Evans has won eight of his past nine matches, including a title run at the $100k ATP Challenger Tour event in Aptos, U.S.A. He will face Wawrinka for the first time.

Evans, who denied 11 of 14 break points faced, while converting six of 14 of his own, was made to work in beating the Emirates ATP Star of Tomorrow. The German teen battled to force a fourth set, taking his seventh set point in the third. But Evans would prove to be too strong in the end, breaking for 2-1 in the fourth and again for 5-2, before closing out the win after three hours and nine minutes. He reaches a second straight third round at a Grand Slam, having advanced as far two months ago at Wimbledon.

“It was probably my best win, [considering] the situation and circumstances,” said Evans. “It was late and difficult mentally. To come back in the fourth and get on top was good. I was a bit passive [in the third set]. He took control. It was pretty evident that’s what he was going to do for the rest of the match. I needed to stay on top of him.”

Where one #NextGen star failed to reach the third round, another succeeded, as American hopeful Jared Donaldson cruised past Viktor Troicki 7-5, 6-3, 6-3. Donaldson, who is projected to crack the Top 100 of the Emirates ATP Rankings for the first time, followed up a first-round upset of David Goffin with a two-hour and 17-minute victory over Troicki. The Rhode Island native is the youngest American to reach the third round at the US Open since 18-year-old Donald Young did so in 2007.

“I’ve been playing well this summer,” said Donaldson. “I’ve also had kind of an average beginning of the year. I’m fortunate that I’ve been able to play so well through the hard courts. It’s really special to be able to culminate the summer and play really well at this event.

“I remember coming here when I was 12. It was really cool to watch all the best players in the world play here. Now I’m thankful that I’m one of those players now.”

One of four Americans in the third round, along with John Isner, Jack Sock and fellow qualifier Ryan Harrison, Donaldson will next face big-serving Croatian Ivo Karlovic. Karlovic polished off Donald Young 6-4, 7-6(4), 6-4 on Thursday, firing 24 aces in total.

Juan Martin del Potro took a stroll down memory lane at the US Open on Thursday, emerging with a convincing 7-6(5), 6-3, 6-2 second-round win against American Steve Johnson on the site of his greatest triumph. The Argentine wild card won the 2009 US Open title against Roger Federer on the same Arthur Ashe Stadium court and returned to Flushing Meadows seven years later older and wiser.

“I’m trying to play as I was in 2009, but it’s not easy as I’m getting older. I took all my chances during the match, and at the end I played very well,” del Potro told ESPN’s Brad Gilbert during an on-court interview after the match.

Del Potro’s huge popularity meant that he was on equal footing with Johnson when it came to crowd support. Both players were evenly matched in the first set until the Argentine’s superior serving made the difference in the tie-break. Johnson bounced right back, breaking for a 2-1 lead in the second set by ripping a massive forehand pass from 10 feet behind the baseline before holding at love for 3-1.

The surge represented the high point of Johnson’s evening. Del Potro drew on his positive memories at Flushing Meadows to capture 20 of the final 22 points of the second set. Unable to find a solution against del Potro’s inside-out forehand attack, Johnson dropped serve in the opening game of the third set and again at 2-4 before succumbing in two hours and eight minutes. He finished with 24 winners and 35 unforced errors while del Potro fired 33 winners and only made 23 unforced errors.

“I think the fans are proud to see me playing tennis again after all my surgeries,” del Potro said in his post-match press conference. “They know what I have been through. I’m having great days at the US Open. I am really enjoying the attention from the fans around the world.

“I served much better than in my first-round match. I focused on the important moments of the game. I played great in the tie-break. At the end, I saw him physically a little tired, so I took all my chances to close out the match in three sets.”

“I just didn’t execute my game plan tonight,” Johnson said. “I had a chance to do well in the second, had my chance to get back on serve in the third. I’ve been winning a lot of those points in the past three months. Unfortunately today I didn’t win those points to get back in it. 

“He’s a great player. Look, he’s 6’6″, great serve, can move well, long wingspan, gets his racquet on a lot of balls. That’s why he’s a Grand Slam champion. He’s no slouch.”

The Argentine has not been past the third round of a Grand Slam event since his semi-final showing at Wimbledon three years ago and last made the second week of the US Open in 2012, when he reached the quarter-finals.

Ivo Karlovic backed up his historic first-round win with a solid follow-up performance against Donald Young. The Croat, who blasted a US Open-record 61 aces in his opening match against Yen-Hsun Lu, added 24 to his tally in beating the American left-hander 6-4, 7-6(4), 6-4. Karlovic had 52 total winners and saved all six break points faced in the two-hour, 20-minute match. He will take on #NextGen star Jared Donaldson in the third round. The 19-year-old Donaldson is the youngest American to reach the third round at the US Open since Young in 2007.