Los Angeles: Second seed Sam Querrey, peaking at just the right time, saved a match point in the second set before upsetting top-seeded Briton Andy Murray 5-7 7-6 6-3 to retain his LA Open title on Sunday.

The big-serving American, who had not won a single set in four previous meetings with Murray, produced his best tennis of the week to wrap up victory in two hours 22 minutes at the LA Tennis Centre.

After breaking the world number four in the sixth game of the final set, Querrey clinched his fourth ATP Tour title of the year, and his sixth overall, when his opponent hit a backhand service return long.

The 22-year-old punched his right fist into the air in delight after becoming the first player to win back-to-back LA Open crowns since fellow American Andre Agassi in 2002.

"This feels great," a beaming Querrey told reporters after winning his fourth successive three-set match of the week. "You're never out of it. You can't give up.

"Today on the break point in the second set and the match point I was just consistent. I wasn't going to give it to him. I was going to make him come up with a shot to beat me."

The 6-foot-6 Californian, ranked 20th in the world, was overjoyed after avenging his loss to Murray in the fourth round at Wimbledon four weeks earlier.

"That's the highest-ranked guy I've ever beat," Querrey said. "The last two sets today were great. I hit some great forehands, I served well when I needed. That was some of the best tennis I've played."

Murray, bidding for his first title of the year in his first tournament back since his semi-final loss to Rafa Nadal at Wimbledon, was satisfied with his week.

"Obviously I'm disappointed to lose but you've got to take the circumstances into consideration," said the 23-year-old Scot.