Roberta Vinci beats Petkovic in 2nd round in St. Petersburg

Defending champion Roberta Vinci advanced to the quarterfinals at the St. Petersburg Ladies Trophy by beating Andrea Petkovic 6-4, 6-4 Thursday.

The sixth-seeded Italian was broken twice in the first set.

Vinci will next face either Australian Open finalist Venus Williams or Kristina Mladenovic.