Isner ousts defending champion
John Isner beat defending champion Ryan Sweeting on Friday to reach the semi-finals of the US Men's Clay Court Championship in Houston.
Second seed Isner edged past fellow American Sweeting to book his place in the last four with a 7-6 (7/1) 7-6 (7/4) win.
Neither player could find a break in either set, but Isner played the clutch points better, saving six break points in dominating both tie-breaks.
"I've always wanted to do well here, so I'm glad I've improved on my previous results," Isner told the ATP World Tour's official website.
"But if I want to get to the final and win this tournament, I'm going to have to play better. Tonight, I don't think either of us played well. I was just luckier."
He will next face third seed Feliciano Lopez, who advanced when Carlos Berlocq retired with the Spaniard winning 6-4 2-2.
The other semi-final will be between fourth seed Juan Monaco and qualifier Michael Russell.
Argentinian Monaco beat Kevin Anderson 7-6 (7/4) 7-5, while Russell edged his all-American clash with Ryan Harrison 6-1 5-7 6-3.