ATLANTA (AFP) - Top-seeded John Isner kept his bid for a third straight ATP Atlanta Open crown on track on Friday, booking a semi-final clash with fellow American Denis Kudla.
Isner needed one hour and 21 minutes to get past Lithuanian Ricardas Berankis 7-6 (7-5), 6-4.
A day after his 33-ace outburst against Radek Stepanek, Isner blasted 19 aces and converted his lone break chance against Berankis.
The 30-year-old booked a first career meeting against Kudla, a qualifier who defeated Israel's Dudi Sela 7-5, 6-0.
The other semi-final will pit fifth-seeded Cypriot Marcos Baghdatis against seventh-seeded Gilles Mueller of Luxembourg.
Baghdatis upended second-seeded Canadian Vasek Pospisil 6-4, 7-6 (7-5) to reach his third semi-final of the season, while Mueller dispatched Japan's Go Soeda 7-5, 6-1.
Isner said he was expecting a tough match against Kudla, who as a qualifier has won five matches in six days to reach his first ATP semi-final.
Kudla converted six of 11 break chances against Sela to wrap up the win in just 61 minutes.
"He's very solid," Isner said of his 22-year-old compatriot. "He returns really well. He's quick. The best part of his game is that he stays very composed out there and doesn't let things rattle him too much. It's paying dividends.
"He's working really hard and he's very young too, so he's got a great future ahead of him. Me being the elder statesman tomorrow, I need to show him no mercy."