Top seed Andy Murray reached the St Petersburg Open semi-finals with a 7-6, 7-5 win over Serbia's Janko Tipsarevic on Friday.
Murray, who won the US $1 million tournament on his debut appearance in Russia's second city last year, remained on course for his second title in two weeks after clinching the Madrid Masters last Sunday.
Murray had to work hard to overcome a spirited challenge by his unseeded opponent.
After edging the first set on a tiebreak, which he won 7-5, the world number four broke Tipsarevic in the third game of the second set only for the 48th-ranked Serbian to break back straight away.
However, Murray was not to be denied as he secured another break in the 11th game before holding his own serve to love to close out the match after two hours and 10 minutes.
"It was a tough win," the 21-year-old Scot told reporters. "But I tried to keep myself concentrated, played every ball up to the end and it worked."
In Saturday's semi-final, he will face third-seeded Spaniard Fernando Verdasco, whom he soundly beat in last year's final. The world number 16 defeated unseeded German Rainer Schuettler 7-5, 6-2 in the earlier match on centre court.
"I lost to Murray in the final last year, so this time I'm hoping for revenge," Verdasco said. "To do that I will have to be more confident in myself and use my chances."
The second semi-final will feature unseeded Romanian Victor Hanescu and Kazakh qualifier Andrey Golubev.
The 66th-ranked Hanescu eliminated local hope Michail Elgin 6-1, 6-4 ending Russia's interest in the tournament.
Elgin, world number 145, was the only Russian to reach the last eight after Nikolay Davydenko, Marat Safin, Mikhail Youzhny and Dmitry Tursunov all fell by the wayside in earlier rounds.
He had been given a free passage into the quarter-finals after second seed Davydenko pulled out of their second-round match with a wrist injury.
The 150th-ranked Golubev, who upset former world number one Safin in the previous round, edged out German qualifier Mischa Zverev 6-7, 6-4, 7-6 to reach his first ATP semi-final.
"This has been a dream week for me," Golubev, 21, who has played mainly on the Challenger circuit and has won only three ATP matches in his career until this week, told reporters.
"But I don't want to stop here. I want this dream to go on."