Top-seeded Mikhail Youzhny saved a match point to beat Victor Hanescu of Romania 6-7 (5), 6-3, 7-6 (6) and reach the St. Petersburg Open semifinals for the fourth time on Friday.
Youzhny, the 2004 champion and 2002 finalist, will take on Dmitry Tursunov after his fellow Russian beat Alexandr Dolgopolov of Ukraine 6-4, 6-2 for his first semifinals in 16 months.
Mikhail Kukushkin of Kazakhstan and Illya Marchenko of Ukraine earned their second career semifinal appearances 12 months after their first semis on tour in Moscow as qualifiers.
Hanescu's fourth ace of five overall won him the first-set tiebreaker. Youzhny broke early in the second set and held on to it.
In the decider, Hanescu saved a break point and Youzhny fought off two and saved a match point at 5-4, 40-30 down on his serve. But in the tiebreaker, Hanescu, the runner-up in 2008, saved a match point before Youzhny beat him with a forehand at 6-all to earn another one.
''If not for my serve, it hardly would have come to the third set,'' said Youzhny, who served nine aces and wasn't broken.
Youzhny, 2-2 in ATP finals this season, served a winner to finish the 2-hour, 47-minute quarterfinal.
Kukushkin beat his second seed of the week in third-seeded Janko Tipsarevic of Serbia 7-5, 3-6, 6-4, while Marchenko ousted Benjamin Becker of Germany 6-4, 2-6, 6-2.
The 88th-ranked Kukushkin constantly dragged Tipsarevic into long rallies and wore him down.
Facing set point in the 12th game of the first set, Tipsarevic netted a forehand to end a 31-shot rally and lose the set.
Tipsarevic then won four games in a raw in the second to level the match, and jumped to 4-2 in the decider. But Kukushkin broke back with a lucky net cord in the seventh game, made another break in the ninth, and served the winner on his second match point.
''It was a tough match and Janko served hard today,'' said Kukushkin. ''It was tough to get a chance on receiving but I was lucky to do it at 6-5 in the first set. And I was really lucky to have a net cord on a break point in the third set to break back and turn the match my way.''
Tipsarevic served 10 aces but converted only three of 11 break chances.
''I'm really disappointed that I've lost,'' said Tipsarevic. ''With the chances that I had, I shouldn't have lost this match. But during the whole match, every time when I had a chance Mikhail was playing some crazy shots. He played too good on important points.''
Marchenko broke Becker at love in the decisive ninth game of the first set, but Becker won four consecutive games in the second to send the match into a third. The Ukrainian then won five consecutive games and served the match out at love.
''I played aggressive tennis in the first set and won it,'' Marchenko said. ''But I could not deal with my emotions when I felt the approach of the victory in the second set. I'm happy I could get back to my tennis in the third set.''
