Second seed John Isner improved to 25-4 at the BB&T Atlanta Open with a dominant 7-5, 6-4 quarter-final win on Friday over Lukas Lacko.

“I think most importantly, I’m at home in the United States and playing on my favorite surface. It’s one of the reasons I do well,” said Isner. “I don’t want to jinx it, but I’ve always played well here. I love this tournament and have fortunately been healthy enough to keep coming back here.”

Going back to his title win last week in Newport (d. Ebden), the American has held in 60 consecutive service games. He faced a break point at 3-4 in the opening set against Lacko, his first in 53 service games, but got out of trouble with a big serve. Isner captured the lone break in each set to advance in 73 minutes.

Isner has reached the semi-finals in Atlanta for all eight years of the tournament’s existence, and played in the final for six of the past seven years. He won the tournament in 2013-2015 and finished runner-up in 2010, 2011 and 2016.

Next up for Isner is third seed Gilles Muller, who comfortably dispatched qualifier and #NextGenATP American Tommy Paul 6-3, 6-1. Muller fired 16 aces and broke his opponent four times in the contest. The 34 year old, currently at a career-high Emirates ATP Ranking of No. 22, moves into his fifth ATP World Tour semi-final of the season.

Isner leads his FedEx ATP Head2Head with Muller 3-2, but Muller has won their past two matches. However, Isner has won both of their previous meetings in Atlanta, with the American scoring deciding-set wins in 2010 and 2011.

“It’s certainly going to be a heavyweight fight tomorrow,” said Isner. “I know he’s beaten me a few times and I’ve beaten him a few times. There’s usually a tie-break involved because of how we both serve. We’re both playing with a lot of confidence. It should be a very good tilt and I’m looking forward to it.”

Fourth seed Ryan Harrison ended the dream run of fellow American and college tennis star Christopher Eubanks with a 6-1, 6-2 victory. Eubanks, a rising senior at Georgia Tech, won his first two ATP World Tour main draw matches this week and clearly thrived on playing in his hometown. But he was no match for the more experienced Harrison, who didn’t face a break point and needed just 55 minutes to secure the win.

Awaiting Harrison in the semi-finals will be top seed Jack Sock or fifth seed Kyle Edmund. Harrison hasn’t played Edmund before, but is even with Sock in their FedEx ATP Head2Head at 1-1. Sock won their most recent match this past January in Auckland. 

#NextGenATP Akira Santillan feels like now is his time to flourish on the ATP World Tour.

The 20 year old recently earned the biggest victories of his career – winning his first ATP Challenger Tour title earlier this month in Winnetka and claiming his first ATP World Tour win at the Dell Technologies Hall of Fame Open in Newport (d. Mmoh).

Santillan has also resolved a nagging dilemma that had been weighing on his mind and affecting his play: Which country should he represent?

The right-hander was born in Japan to his South African father, Dean, and his Japanese mother, Harumi. But the family moved to Australia for Akira’s tennis when he was about seven, and Akira lived Down Under until he was about 18. (He trains in Spain now.)

In early 2015, Santillan decided to play under the Japanese flag. But at Wimbledon, he switched his allegiance to Australia.

“My parents live in Australia. My dad has been living in Australia since he was 13, and I’ve been living there since I was seven… For me, I felt more comfortable playing for Australia,” Santillan exclusively told ATPWorldTour.com. “I’ve been thinking about it for at least over a year now… I felt like I needed to make a decision. I can’t be always wondering in my mind who I’m going to play for, so I think that has cleared things up a bit. It lets me play a little bit freer.”

The relaxed feeling helped Santillan experience his milestone wins in Illinois and Rhode Island. Before Winnetka, Santillan had reached three ATP Challenger Tour semi-finals but he had fallen in the third set during all three. They had been close deciders, too: 7-5, 6-4, 6-4.

In Illinois, after he took the first set 6-4 against German Matthias Bachinger, Santillan later admitted doubts snuck into his mind.

“I was winning comfortably and then I had a hiccup and I found myself in the third set, and I was thinking about it a little bit again,” Santillan said of his past semi-final losses. “But I got through that… I just focused on my game. I was playing really well so there was no reason to be really tight or anything. I went through, won the third set quite comfortably and then the final was pretty straightforward. I played really well, pretty smart tennis. Overall I was really happy with the tournament.”

At the grass-court tournament in Newport, Santillan’s aggressive game thrived as he earned his first ATP World Tour win during his third attempt. “I played really well, and I’m pretty pleased with myself,” Santillan said.

The right-hander’s game favours such quick surfaces. Santillan tries to play an all-around game, a necessity during this era of tennis that has been dominated by do-everything players Novak Djokovic, Andy Murray, Roger Federer and Rafael Nadal.

“I play pretty aggressive with my forehand… I can play anywhere on the court. I like to come to the net. Change pace on my slice. Use my forehand to dominate play. I think I have a pretty good serve, a pretty big serve,” Santillan said. “You need every weapon that you can get. On the tour nowadays, everyone has a weapon – they can defend, they can attack, they’ve got everything.”

Santillan has other big goals to complete this season. The #NextGenATP Aussie, No. 160 in the Emirates ATP Rankings, would like to crack the Top 100. He’d like to qualify for the US Open, the season’s last Grand Slam tournament.

Santillan also might find his way into the Next Gen ATP Finals, to be held 7-11 November in Milan. He is currently in 16^th place in the Emirates ATP Race To Milan, which will determine seven of the eight 21-and-under players who compete at the inaugural event. The eighth player will be chosen by wild card. Santillan is 222 points behind eighth-placed American Jared Donaldson.

“I feel really confident right now with my game. I feel like I’m seeing the ball like a basketball,” Santillan said. “It’s going to be fun and exciting to see how I can do.”

See Who’s Leading The Emirates ATP Race To Milan

Robin Haase came alive in The Alps once more, just as he has done in two previous runs to the J. Safra Sarasin Swiss Open Gstaad final, when the Dutchman ended David Goffin’s bid for a third ATP World Tour title on Friday.

Haase began in fine style by breaking for a 2-0 lead, and while his top-seeded Belgium opponent stayed in contention, World No. 50 Haase won seven straight games from 5-5 in the first set en route to a 7-5, 6-1 victory in 81 minutes. It was his first win in four meetings against Goffin, the 2015 runner-up (l. to Thiem).

“Today it was a bit more windy and we were both a bit nervous at the beginning,” said Haase. “I really enjoy the conditions here and I’m happy to be back in the semi-finals.”

Sixth seed Haase, the 2013 (l. to Youzhny) and 2016 finalist (l. to Lopez), now faces qualifier Yannick Hanfmann. The World No. 170 could not convert two set point opportunities in the first set, but bounced back to knock out eighth seed Joao Sousa 6-7(10), 6-2, 6-2 in one hour and 56 minutes. Hanfmann, who has played just eight tour-level matches, could not seal set point chances at 7/6 and 9/8 in the first set tie-break.

Second seed Roberto Bautista Agut lost just six of his first-service points to beat Denis Istomin 6-3, 6-4 in 80 minutes to improve to a 31-12 match record in 2017. “Today, the conditions were a bit faster than the other days and Denis played aggressively,” said Bautista Agut. “I will prepare and rest well for tomorrow.”

The Spaniard next faces fourth seed Fabio Fognini, who broke Ernests Gulbis three times to advance 6-3, 4-6, 6-3 in one hour and 50 minutes. Gulbis had led their FedEx ATP Head2Head series 4-1, including 2-0 on clay, before Friday.

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Marach/Oswald Advance To Doubles Final
Second-seeded Austrians Oliver Marach and Philipp Oswald booked their place in the Gstaad final by beating third seeds Roman Jebavy and Matwe Middelkoop 6-3, 6-3 in 60 minutes. Marach, 15-21 in doubles finals, partnered Aisam-Ul-Haq Qureshi to the 2015 title match (l. to Bury-Istomin). Oswald will be looking to improve his 4-2 record in finals.

Fourth seeds Jonathan Eysseric and Franko Skugor will take on Dutchmen Sander Arends and Haase in the other semi-final on Saturday.

Novak Djokovic owned 2015. Andy Murray surged to World No. 1 in 2016, and it’s been the Roger and Rafa show so far in 2017.

The Big Four have all had their time in the sun during the past two-and-a-half years, and all are ranked in the Top Four of the Emirates ATP Rankings this week.

An Infosys ATP Beyond The Numbers breakdown of their first-serve percentage when serving down break point in both the deuce and ad courts from the 2015 season to the present time provides deeper insight into the metrics that define their greatness.

1. Overall Record
Novak Djokovic has the highest match-win percentage of the Big Four since the start of the 2015 season, at 88.6 percent, with Roger Federer in second place, at 85.2 per cent.

Big Four Overall W/L Record 2015 to Present

2. Deuce Court – First-Serve Percentage Down Break Point
Nadal is the clear leader in this category, making 73.7 per cent of his first serves in the deuce court down break point. The primary pattern for the lefty is to hit a slice serve down the centre of the court, and follow it up with his trademark “Serve +1” forehand.

Deuce Court – First-Serve Percentage Down Break Point

3. Ad Court – First-Serve Percentage Down Break Point
Nadal leads in this category as well, but it’s interesting to note that he makes just 0.2 per cent more first serves in the ad court than the deuce court. Djokovic improved the most in the ad court over the deuce court, up 4.3 percentage points, while Federer and Murray both made fewer serves on this side.

Ad Court – First-Serve Percentage Down Break Point

4. Overall – First-Serve Percentage Down Break Point
Overall the Big Four played 77.5 per cent of their break points in the ad court. Only Nadal and Djokovic combined to make above 65 per cent of their first serves in both courts during this crucial time of the match.

Overall First-Serve Percentage Down Break Point

5. Summary
Putting a first serve in the court when all the drama is unfolding around a break point comes down to simple technique, holding your nerve, and coming up with the the right serve – a flat, slice or kick serve – and placing it in just the right spot – out wide, at the body or down the centre.

The Big Four don’t always follow the same playbook as each other, but their proven dominance at the top of our sport since the start of the 2015 season comes down to owning moments in time just like this.