This week’s $100,000 ATP Challenger Tour event in Tiburon, California, has long been known as one of the most respected tournaments on the calendar, but now it will also be known for holding a record that likely won’t be broken anytime soon.

On Wednesday, Canadians Philip Bester and Peter Polansky won a marathon 20-18 second set tie-break in their opening round doubles match over Darian King of Barbados and American #NextGen star Frances Tiafoe. The 38-point tie-break is the longest in Challenger doubles since the ATP began keeping records for such doubles matches in 2007. Bester/Polansky saved multiple match points to prevail in the tie-break.

Including ATP World Tour matches, it is the second-longest tie-break, only behind a 25-23 marathon in a first-round clash in Washington, D.C. in 2015, which saw Colombians Juan Sebastian Cabal/Robert Farah prevail over Austin Krajicek/Nicholas Monroe. These tie-break stats do not include Match Tie-breaks.

“It was a pretty insane tie-break. Every match point and set point was long and they all ended with a ridiculous shot,” said Polansky. “It’s one of the most entertaining matches I’ve played in my entire career.”

Bester added that “it was a fun ‘breaker to be a part of. I thought it was never going to end.”

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But while the Canadians won the battle, King and Tiafoe won the war. They regrouped after dropping the marathon tie-break to take the match, 7-6(2), 6-7(18), 10-8. King/Tiafoe rallied from 0-4 down in the Match Tie-break.

“I sat down in the chair at 18-all and was thinking, ‘This is the craziest thing that’s ever happened.’ I remember Bester saying that he’s never been a part of anything like this. That was good fun,” said Tiafoe. “When we got to match point at 9-8, I was thinking we had to end it there and we did.”

“We had a lot of fun and the crowd really enjoyed it,” added Tiafoe. “There were some extremely lucky shots, but we all stepped up on the big points. You just try to stay in the moment as much as possible and make a lot of first serves.” 

Next up for King/Tiafoe is a quarter-final match on Friday against Americans Sekou Bangoura/Mitchell Krueger. 

Already a four-time ATP World Tour champion this season, 23-year-old Dominic Thiem is riding high on his formula for success. The co-leader with Novak Djokovic for match wins this season, on 56, the Austrian is on track to qualify for his first Barclays ATP World Tour Finals.

An often unrecognised statistic in his winning ways, though, is his enviable tour-leading 21-1 record in deciding sets for the year to date. “Every time I read it I’m impressed about the statistic,” Thiem laughs.

It is a huge improvement on last season, a combination of factors the Austrian puts down to luck, fitness and a healthy dose of confidence.

“A lot of things have an influence,” he said. “First of all, in the first couple of tournaments of the year I was a little bit lucky to win a few third sets. Then of course if you have a 5-0, 6-0, 7-0 record in the decider, you have a lot of confidence.

“The other thing is on clay it’s very hard to play against me. It’s heavier I think and physically tough for the opponent. That’s also the reason and of course my fitness and mental game have improved on last year.”

Despite the impressive record Thiem doubts it enters his opponents’ minds, should they find themselves in a deciding set against him. They are more focused on what they need to do to get across the line.

“Nobody really thinks about it when it goes to the deciding set,” he said. “I don’t think somebody goes in thinking they’re scared because I have such good statistics.”

It serves as a welcome confidence boost in the back of his mind if the match is all square and heading to a final set. “I think so yeah. I think last year was different,” he said.

“I lost more than I won. I think if it comes to a decider I have a very good record there so you have a bit better feeling than normal.”

So who claims bragging rights as the only player to have taken the deciding set against Thiem in 2016? That goes to Philipp Kohlschreiber, a third-set tie-break winner in the BMW Open final in Munich.

“Nothing went wrong,” he laughed. “He played really good and he deserved to win that actually. I was really lucky it came to a decider.”

 Here’s a look at the Top 10 deciding-set match wins leaders for 2016 to date.

Third seed Richard Gasquet is through to the Shenzhen Open semi-finals after edging qualifier Mischa Zverev 7-6(4), 7-6(2) on Friday.

The Frenchman prevailed in just over two hours to claim his 28^th win of the season. Zverev had not dropped a set in advancing to his first ATP World Tour quarter-final in almost a year, but came up just short against Gasquet, despite saving 11 of 14 break points. The German was looking to reach his first semi-final in six years.

The 30-year-old Gasquet is chasing his second ATP World Tour title of the season, following victory in Montpellier in February (d. Mathieu). It has been, at times, a frustrating year for the right-hander, hampered by back, rib and abdominal injuries. But he is looking to get back on track after a surprise first-round defeat to Kyle Edmund at the US Open.

Gasquet goes on to face Malek Jaziri or Janko Tipsarevic for a place in his 26^th ATP World Tour final.

Russian #NextGen star Karen Khachanov is through to his first ATP World Tour semi-final after taking down his second seeded opponent at the Chengdu Open on Friday. The 20-year-old Muscovite defeated fourth seed Feliciano Lopez 6-3, 6-4.

In the first FedEx ATP Head2Head meeting between the pair, it was the young Russian who outshone the Spaniard on serve, sending down 10 aces and conceding just six points on his first serve. He did not face a break point throughout.

Lopez, a winner in Gstaad this season, was attempting to reach his fifth ATP World Tour semi-final of the season. He was broken once in each set and it was enough for the player 15 years his junior to close it out in one hour and 14 minutes.

It was only Khachanov’s third ATP World Tour quarter-final, the second of the season after Kitzbuhel. He had taken down seventh seed Joao Sousa and Frenchman Adrian Mannarino en route and awaits sixth seed Viktor Troicki.

Troicki was a 6-3, 7-6(4) winner over Kevin Anderson, advancing in one hour and 31 minutes as he struck 12 aces and lost only nine points on serve.

“He beat me last time so I’m happy to tie things up between us,” said Troicki. “He’s a good player and he was in the Top 10 last year. It was a big game, but today I had my day, I played really good, I am happy. I returned his serve and in general, I am happy overall.”

Looking ahead to the clash with Khachanov, Troicki added, “I have never played him but he’s a talented young player. He proved that he can play big tennis, big games. I watched his match against Lopez. He really deserved to win. He played really aggressive tennis. I have to play really good to beat him and it’s not going to be easy. Hopefully I’ll give my best, enough to win the match.”

The 30-year-old Troicki is chasing his second title of the season after hoisting the trophy in Sydney at the start of the year. He was also runner-up in Sofia (l. to Bautista Agut) and has a 29-23 record on the season.

Top Seeds Reach Doubles Final

Top seeds Raven Klaasen and Rajeev Ram reached their fourth ATP World Tour final of the season as they defeated Nicholas Monroe and Artem Sitak 6-4, 7-6(5). The South African/American duo, winners already this year in Halle, are currently seventh in the Emirates ATP Doubles Race To London and bidding to qualify for the Barclays ATP World Tour Finals for the first time.

“One of the things that we’re trying to improve on is our record in finals,” said Ram. “We only won one out of three this year, so we will try to play better. No matter who our opponents are, it is going to be a tough match.”

Dominic Thiem ended a memorable run by one of China’s top-ranked players at the Chengdu Open on Thursday. The top seed dismissed Di Wu 6-4, 6-4 in 67 minutes to move into the quarter-finals.

Wu was going for more personal history at his home tournament. The Chinese No. 2 celebrated his first ATP World Tour or Grand Slam main draw match win during his 14^th try on Tuesday (d. Kravchuk). Against Thiem, Wu was trying to earn his first Top 10 victory.

But the Austrian won almost 80 per cent of his first-serve points and broke Wu four times to reach his 13^th ATP World Tour quarter-final of the season. Wu fell to 0-10 against Top 10 foes.

“He was playing very well. My coach knew him so he gave me some very good tips,” Thiem said. “He was serving better than expected… He played a really good match.”

Thiem, who was a finalist in Metz last week (l. to Pouille), is trying to make his seventh final of the season. He’s also looking to bolster his chances of qualifying for the Barclays ATP World Tour Finals for the first time. The 23 year old is currently in seventh place in the Emirates ATP Race To London. The top eight qualify for the year-end championships, to be held 13-20 Nov. at The O2 in London.

If Thiem wins the Chengdu title, he would add 70 points to his haul. Right now, sixth-placed Gael Monfils leads him by 150 points.

In the quarter-finals, Thiem will face fifth seed Albert Ramos-Vinolas for the first time. The Spaniard beat 33-year-old Yen-Hsun Lu of Chinese Taipei 7-6(4), 3-6, 6-4.

“He’s a great player, and I had to run a lot. The match was so close,” Ramos-Vinolas said. “Very happy [with the win]. It’s not easy to play Lu in Asia.”

Who’s Close To Qualifying For The Year-End Championships? View The Emirates ATP Race To London

Defending champion Tomas Berdych stayed undefeated at the Shenzhen Open on Thursday. The top-seeded Czech delivered 16 aces and withstood a tight contest from Kazakhstan’s Mikhail Kukushkin to move into the quarter-finals 7-6(7), 7-6(4) in about two hours.

Berdych and Kukushkin both won exactly 84 points during their second-round match but the Czech was more clutch when the match was on the line. Serving at 5/4 in the second-set tie-break, Berdych delivered his 16^th ace. Kukushkin netted a backhand on match point to give Berdych his fifth consecutive win in Shenzhen.

“It wasn’t easy at all,” said Berdych.

The 31-year-old right-hander is trying to reach his first final of the season. The nine-month drought is the longest Berdych has gone without a final to start a season since 2011, when he won Beijing on 9 Oct. (d. Cilic). The 6’5” right-hander is also attempting to qualify for the Barclays ATP World Tour Finals for the seventh consecutive season.

Berdych is currently No. 9 in the Emirates ATP Race To London, 580 points behind eighth-placed Rafael Nadal. The top eight qualify. But Berdych could cut the Spaniard’s lead to 330 points if he repeats in Shenzhen and claims the 250 Emirates ATP Rankings points up for grabs this week.

Berdych will next face countryman Jiri Vesely, who beat Spaniard Inigo Cervantes 7-6(2), 6-3 during Thursday’s final match on Centre Court. Berdych leads their FedEx ATP Head2Head series 2-0, including a 6-3, 6-2 victory in the Shenzhen quarter-finals last year.

Who’s Ahead Of Berdych? View The Emirates ATP Race To London Standings