Roberta Vinci survived a scare from Timea Babos of Hungary to reach the St. Petersburg Ladies Trophy semifinals on Friday.
Vinci broke Babos when the latter was serving for the match in the deciding set, and bounced back from 4-2 down in the tiebreak to win 7-6 (3), 4-6, 7-6 (4).
Vinci struggled throughout the first and second sets, landing fewer than half of her first serves.
Vinci said she had been "so tight, so nervous" at the start but "I stayed focused and I won a great match."
The second-seeded Vinci awaits either fourth-seeded Ana Ivanovic or Ukrainian qualifier Kateryna Kozlova.