Top seed Andy Murray battled against his serve as well as Alejandro Falla, but claimed a 7-6 (7-3) 6-1 win to reach the semi-finals of the Farmers Classic in Los Angeles.

Murray's first-serve percentage was just at 42 for the match and an incredible 38 percent for the second set, but he met an opponent who struggled as much as he did.

And after battling through a tough opening set, the second, despite his service struggles, was far simpler as Murray, without a coach after he split with Miles Maclagan this week, sealed a last-four clash with Feliciano Lopez.

Fourth seed Lopez ended American James Blake's run with a 3-6 7-6 (8-6) 6-4 win.

Second seed Sam Querrey came through testing quarter-final against Rainer Schuettler with a 6-2 3-6 7-6 (7-4) win, despite the veteran German twice serving for the match.

After going a set down, Schuettler battled back to claim the second, then broke to go 5-4 up in the third.

Querrey levelled, but again surrendered on serve, before breaking back for a second time to send the match into a tie-break, which he won.

"I was pretty frustrated the whole time, but I did a great job of playing the 5-4 and 6-5 games," Querrey told www.atptour.com. "I played great points on those games and really battled back well."

Waiting for Querrey in the semis is sixth-seeded Serbian Janko Tipsarevic.

The had a relatively easy time against Marcos Baghdatis, coming through 6-3 7-5 against the third seed.