(CNN) -- Top seed Andy Murray made a winning return to the circuit in his first match since Wimbledon with a three-sets victory over American qualifier Tim Smyczek at the ATP tournament in Los Angeles.
The Scot accepted an invitation to play at the hard court event after world number two Novak Djokovic pulled out and he was tested by Smyczek before reaching the quarterfinals.
Murray eased through the opening set for the loss of a single game, but was broken three times as his opponent forced a decider.
But the world number four was never troubled again and completed a 6-1 4-6 6-2 victory to earn a last eight clash against Alejandro Falla of Colombia on Friday night.
Murray was also playing his first match since firing his coach of the past two and a half years Miles Maclagan and he showed signs of ring rust after a layoff since losing to Rafael Nadal in the semifinals at Wimbledon.
"The first set was good and I started the second set with chances," said Murray. "I was struggling a little bit with my movement, when I got stiff and sore. But I managed to find a way to win," he told the official ATP Tour website.
Murray has been training hard at a camp in Miami ahead of a tilt at the U.S. Open next month.
Falla upset fifth seed Ernests Gulbis of Latvia 3-6 6-4 7-6 to line up his clash with Murray.
American hope James Blake reached his first quarterfinal since February as he beat German Benjamin Becker 7-5 7-6.
Blake, who has slipped out of the top 100, will next meet fourth seed Feliciano Lopez of Span, who put out Israeli Dudi Sela in straight sets.