The top ace leaders in this year’s Infosys ATP Scores & Stats served their way into the second round of the Erste Bank Open 500 on Monday in Vienna.

Eighth seed Ivo Karlovic, the top ace hitter before Monday with 1,003, blasted 16 more while beating Steve Johnson 7-6(5), 6-3. Karlovic, who also swept Johnson in Washington, saved all six break points against the American, who reached his first ATP World Tour final in Vienna last season (l. to Ferrer).

View more statistics at the ATP Stats LEADERBOARDS

The 37-year-old Croatian will meet Bosnian qualifier Damir Dzumhur, who outlasted Spaniard Nicolas Almagro 6-3, 5-7, 6-0 in one hour and 40 minutes.

John Isner, who entered Monday second in aces with 997, struck 18 aces and saved all seven break points in his comeback win against German Jan-Lennard Struff 6-7(1), 6-3, 6-4. The American, who now has 1,015 aces, surpassed the 1,000 mark for the fourth time in his career. He also did in 2010, 2012 and 2015.

Karlovic has led the ATP World Tour in aces five times: 2007-09, ’14-15; Isner, three times: 2010, ’12-13. Isner will look to pad his total against seventh seed Lucas Pouille or Spaniard Feliciano Lopez in the second round.

The youngest player in the Vienna draw also used some efficient serving to advance. Russian wild card Karen Khachanov won 82 per cent of his first-serve points to dismiss Italian Andreas Seppi 6-4, 6-4 in 69 minutes. The 20 year old, a member of the ATP Next Generation, captured his maiden title earlier this month at the Chengdu Open (d. Ramos-Vinolas). Khachanov will next face second seed Tomas Berdych or Georgian qualifier Nikoloz Basilashvili.

Berdych is trying to make a final push to the Barclays ATP World Tour Finals. The Czech is currently in ninth place in the Emirates ATP Race To London, 325 points behind eighth-placed Dominic Thiem, who’s the third seed in Vienna, his home tournament.

View the Emirates ATP Race To London standings

Andy Murray continues his quest to take the World No. 1 spot from Novak Djokovic at this week’s Erste Bank Open 500 in Vienna.

If Murray wins in Vienna and next week’s BNP Paribas Masters in Paris, Djokovic would have to reach the Paris final in order to maintain his No. 1 standing. Djokovic currently has 10,600 points in the Emirates ATP Race to London, while Murray has 9,685 points. Should Murray win in Vienna, the 500 points he would gain would cut Djokovic’s lead over him to 415 points. The BNP Paribas Masters has 1,000 points on offer for the winner, enough for Murray to make a move for World No. 1.

After Paris, the Emirates ATP Race to London and the Emirates ATP Rankings will mirror each other. Murray must win in either Vienna or Paris if he is to have any chance of holding the top spot in the Emirates ATP Rankings before the Barclays ATP World Tour Finals. But even if he prevails in both events, it’s not a guarantee Murray would unseat Djokovic.

Below are the scenarios in which Murray would move into the No. 1 position on Nov. 7.

· If Murray loses in the first-round of Vienna, he must win in Paris and Djokovic must lose beore the third round.

· If Murray loses in the second-round or quarter-finals of Vienna, he must win in Paris and Djokovic must lose before the quarter-finals.

· If Murray loses in the semi-finals of Vienna, he must win Paris and Djokovic must lose before the semi-finals

· If Murray finishes runner-up in Vienna, he must win in Paris and Djokovic must lose before the final

· If Murray wins Vienna, he must win in Paris and Djokovic must lose before the final, or he must reach the Paris final and Djokovic must lose before the semi-finals.

The battle for World No. 1 could be decided at the Barclays ATP World Tour Finals. Djokovic is a five-time winner and four-time defending champion at the season-ending event, while Murray has never reached the final and moved past the round-robin stage in just three of seven previous appearances.

Murray starts his Vienna campaign with an opening round clash against Martin Klizan.

Andy Murray, Tomas Berdych, Dominic Thiem and Jo-Wilfried Tsonga helped kick off the Erste Bank Open 500 on Sunday with a game of mini-tennis in front of Vienna’s world-famous St. Stephen’s Cathedral.

The four top ATP World Tour players, all seeded at this week’s Vienna tournament, also interacted with fans and shared their expectations for one of the season’s final tournaments.

Murray, who’s chasing Novak Djokovic for the No. 1 spot in the Emirates ATP Rankings, is the top seed this week. Two years ago, during his only prior appearance at the tournament, the Scot won the title, defeating David Ferrer in the final. If Murray lifts the trophy on Sunday, he’d celebrate his seventh title of the season, which would mark a career high.

“I played well here last time. I was in the position of trying to qualify for the [Barclays ATP] World Tour Finals at the end of the year, so I was very motivated and managed to win the event,” Murray said. “The centre court is a really, really nice stadium and a great atmosphere. There’s a lot of history at the tournament as well, a lot of great players have played here over the years and won. So it’s a nice event to be part of.”

Murray also has been impressed with Vienna as a city. “When you’re driving around the city, the views are amazing,” he said. “There are great buildings and amazing architecture, and it’s a nice place to visit for sure.”

Berdych, the second seed, wants to finish his season strong. He repeated as champion at the Shenzhen Open earlier this month but fell in his opening matches in Tokyo and Shanghai.

“I’m feeling good. The second half of the year has been a little bit tough, but overall I think I’m ready. I had a good few days of preparation and rest,” Berdych said. “A few interesting things are happening, so I’m really looking forward to the last few weeks of the season.”

The 31 year old is currently in ninth place in the Emirates ATP Race To London, 325 points behind eighth-placed Thiem. This week’s titlist will receive 500 Emirates ATP Rankings points, and next week’s BNP Paribas Masters champion will earn 1,000 points.

“These two weeks are going to be very important. It’s going to be decided by playing good tennis. That’s what will get me through and get me in into the [Barclays ATP] World Tour Finals,” Berdych said. “I’m really just trying to go one by one. I’m here in Vienna. I just want to play some good tennis, starting well in the first match and build it up. Then whatever happens, happens.”

Dominic Thiem, who’s from just outside Vienna, is also hoping to boost his status in the Emirates ATP Race To London standings this week. The 23 year old is 95 points behind seventh-placed Rafael Nadal. Thiem will make his sixth consecutive main draw appearance in Vienna. He has a 4-5 record at his home tournament, with his best result the quarter-finals in 2013.

“Obviously I really love the city,” Thiem said. “I’m really happy that I can play at home.”

The sixth-seeded Tsonga will hope to rekindle old memories this week. He won the tournament in 2011, beating Juan Martin del Potro in three sets.

“I’m feeling good and just happy to be here. It’s a nice city, a nice tournament. I’ve had good matches at this tournament in the past, and I won one time,” Tsonga said. “For me it’s always great to be back. It’s an amazing city, to be honest. I’ve been coming here for a long time now, and it looks like the city has improved every year.”

Main draw play begins on Monday in Vienna, highlighted with Berdych facing off against Georgian qualifier Nikoloz Basilashvili.

A LOOK BACK

International Challenger Ningbo (Ningbo, China): Second seed Yen-Hsun Lu of Chinese Taipei won his 25^th ATP Challenger Tour title with a dominant victory over Hiroki Moriya of Japan, 6-3, 6-1. Lu saved four match points in his semi-final win over sixth seed and #NextGen star Hyeon Chung of Korea. The veteran has been a dominant force at this event, winning three of the four editions of the Ningbo Challenger. He is also the third player to successfully defend a Challenger title this year.

Lu has recorded an outstanding 29-5 record on the ATP Challenger Tour in 2016, winning three titles (Ningbo, Surbiton, Ilkley) and finishing runner-up at two other events (Seoul, Bangkok)

Open Brest Arena Credit Agricole (Brest, France): Lucky loser Norbert Gombos of Slovakia completed an improbable week by sneaking into the main draw due to the withdrawal of French #NextGen star Quentin Halys, then capturing his first title of the year with a win over Yannik Reuter of Belgium, 7-5, 6-2. He is the first Lucky Loser to win a Challenger since 2013, when Jesse Huta Galung won in Cherbourg, France.