ATLANTA (AP) -- Two-time defending champion John Isner ran his Atlanta Open winning streak to 10 matches Friday, riding his big serve to a 7-6 (4), 6-4 victory over Ricardis Berankis.
The top-seeded Isner had 19 aces less than 24 hours after ripping off 33 in a two-set victory over Radek Stepanek. Isner will face training partner Denis Kudla Saturday in his 34th ATP Tour semifinal. Kudla, a qualifier, beat Dudi Sela 7-5, 6-0 to reach his first ATP semifinal.
As a wild-card entry at Wimbledon, the 22-year-old Kudla became the first American male to reach the round of 16 since 2012 before falling to Marin Cilic.
"He's solid, very quick," Isner said about Kudla. "Me being the elder statesman, I need to show him no mercy, but he's playing the best tennis of his life."
In pushing his Atlanta record to 18-3, Isner reached his sixth straight Atlanta semifinal. The 6-foot-10 former University of Georgia player's serve peaked at 138 mph.
Berankis, a Lithuanian ranked No. 87, also served well. He had 10 aces, and won 86 percent of his first serves (to Isner's 84 percent), and 62 percent on seconds.
"The conditions were different (than Thursday night)," Isner said after playing for 80 minutes under relentless sun. "It's faster. It helped my serve so much. The ball was bouncing everywhere. For a guy who is small in stature, (Berankis) crushes the ball . . . There were a lot of short points, which generally works in my favor."
The two pivot points were the first-set tiebreaker, where Isner served first and Berankis returned just two of six serves, and the only break of the match.
That came in the second set. With Berankis serving at 1-1, he went to the net only to bump a backhand long and past an open court to cede the game.
Isner is trying to reach the Atlanta final for the fifth time in six years. He lost in the finals in 2010 and 2011, fell in the 2012 semifinals to eventual champion Andy Roddick, and won the past two years.
On Friday night in the other quarterfinals, second-seeded Vasek Pospisil faced No. 5 Marcos Baghdatis, and No. 7 Gilles Muller played Go Soeda.