Andre Agassi booked his place in the semi-finals of the Mercedes-Benz Cup with a 6-2 4-6 6-4 win over Thailand's Paradorn Srichaphan in Los Angeles. Agassi made a fine start but was taken to a decider after Srichaphan hit back from a break down in the second set.
The top-seeded American will now play Argentine Juan Ignacio Chela, who beat Belgium's Xavier Malisse 6-4 7-6.
Second seed Dominik Hrbaty of Slovakia will play Luxembourg's Gilles Muller in the other semi-final.
Hrbaty saved seven match points in the second-set tie-break, in which he trailed 6-1, as he beat Brazilian Ricardo Mello 4-6 7-6 (9-7) 6-2.
Muller saw off American Robby Ginepri 7-6 (7-5) 7-5.
Agassi is playing his first event since the French Open two months ago, having recovered from a hip problem.
"It's been hard the last eight weeks to be sitting around watching the biggest tournaments in the world pass you by," said the 35-year-old.
"But I'm committed to never again being on court when I'm just limping along. If I'm not healthy I won't be playing.
"I've got three wins under my belt (this week). I didn't know what to expect but each match has gotten better. It feels really good."