LOS ANGELES:- Top seed and former title holder John Isner downed Chung Hyeon 7-6 (7/5), 6-4 on Friday to book a semi-final clash with defending champion Jack Sock at the ATP claycourt tournament in Houston on Friday.
Isner, who lifted the trophy in 2013, saved all seven break points he against the rising South Korean star, firing 14 aces and winning 58 percent of his second serve points.
The US veteran was solid when it mattered most against the 19-year-old Chung, voted last year’s Most Improved Player by his peers.
“That one game in the first set, I was down four break points,” Isner said.
“Serving at 4-3 (in the second), I was down three break points and I had to hit a stab volley on one of them. That was huge. He played a good return game.”
Although he pulled off the win, Isner said he expected to see Chung continue to rise.
“He’s only going to get better, he’s only going to get stronger, he’s going to make all his shots better,” Isner said.