Murray won his second Masters Series title in Madrid on Sunday
Andy Murray was made to work hard as he progressed to the St Petersburg Open semi-finals with a 7-6 (7-5) 7-5 win over Janko Tipsarevic.
Murray's spirited Serbian opponent battled back from a break down to take the first set to a tie break.
In the second set, Tipsarevic again hit back from a break down to take a 4-3 lead, but the British number one broke serve at 5-5 and held for victory.
Murray will play third seed Fernando Verdasco for a place in the final.
Tipsarevic had won two of his three previous matches against defending champion Murray - in the first round at Queen's Club in 2006 and then in Moscow last year.
And there were moments during the quarter-final when it seemed the world number 48 would cause an upset and end the Scot's defence of the title.
Murray, 21, began positively, with two aces in the opening game, and broke in the next before holding to lead 3-0.
But Tipsarevic took the fourth game to trigger a burst of fine tennis.
The Serb looked comfortable and made it 4-4 to take the set to a tie-break, which the world number four won.
Murray again broke early in the second thanks to a sublime crosscourt backhand but, just as in the first set, Tipsarevic fought back.
However, Murray dug deep for a chance to win his fifth title of a hugely successful year.
"It was a tough win, but I tried to keep myself concentrated, played every ball up to the end and it worked," he said.
In the other quarter-final matches, Spain's Verdasco beat Germany's Rainer Schuettler 7-5 6-2.
"I lost to Murray in the final last year, so this time I'm hoping for revenge," said the Spaniard.
"To do that I will have to be more confident in myself and use my chances."
Andrey Golubev of Kazakhstan beat Germany's Mischa Zverev 6-7 6-4 7-6 and will play Victor Hanescu is the other semi-final after the Romanian eased past home favourite Michail Elgin 6-1 6-4.