Australian Open finalist Petra Kvitova won eight straight games to take control of the match before needing a tiebreaker to finally beat Victoria Azarenka 6-2, 7-6 (3) on Wednesday in the second round of the St. Petersburg Ladies Trophy.
Kvitova, playing her opening match after a first-round bye, went from trailing 2-1 in the first set to a 3-0 lead in the second. But she double-faulted on match point at 5-1 to let Azarenka back into the match.
Kvitova will next face either eighth-seeded Donna Vekic or lucky loser Veronika Kudermetova in the quarterfinals.
Maria Sharapova withdrew from the tournament with a right shoulder injury, hours before she was to play Daria Kasatkina in the second round.