St Petersburg - Fourth-seeded Marin Cilic of Croatia and American Alex Bogomolov Jr, seeded seventh, advanced to the second round of the St Petersburg Open with straight-sets victories on Tuesday, while defending champion Mikhail Kukushkin of Kazakhstan made an early exit.
Bogomolov beat Igor Kunitsyn of Russia 6-3, 6-1, while Cilic ousted Ukrainian qualifier Sergei Bubka 6-4, 7-6 (1).
Bogomolov - who was making his debut at a second consecutive event in Russia after reaching the quarter-finals at the Kremlin Cup last week - broke Kunitsyn twice in the first set and three times in the second to win in 1 hour and 6 minutes.
"I know Kunitsyn and the way he plays perfectly," Bogomolov said. "It was important to neutralise his backhand. So, I served hard and returned with maximum concentration."
Kukushkin, who was looking for his second title, was beaten by Michael Berrer of Germany 6-1, 4-6, 6-4. Julien Benneteau of France also advanced with a straight-sets victory over Pere Riba of Spain, 6-2, 6-1.
The 22nd-ranked Cilic is looking for his first title of the season. Cilic broke in the ninth game of the first set but Bubka saved five break points in the 11th game of the second set before the Croat prevailed in the tie-breaker to win on his first match point.
"It was really good for me to go through this match today," said Cilic, who reached the semi-finals here four years ago. "Bubka was serving really good in some moments and especially in the second set on 5-all I had five break points and he served three aces and one service winner, so, it was really tough."