Caroline Wozniacki remains undefeated in New Haven after beating Sofia Arvidsson of Sweden 7-6 6-2 in the second round of the New Haven Open.

Wozniacki is playing in the tournament for the fifth time and is the four-time defending champion. Wednesday’s victory was her 19th here without a loss.

She will play Dominika Cibulkova of Slovakia in the quarterfinals. Cibulkova beat Andrea Petkovic of Germany 6-4, 6-1. Petkovic, who is coming off injuries to her backand right ankle, was playing in her first tournament since April and her fourth of the year.

Second-seeded Petra Kvitova, who received a first-round bye, is scheduled to play her first match of the tournament Wednesday evening against 19-year-old Nicole Gibbs, who is seeking to move into her first WTA quarterfinal.