Caroline Wozniacki eased past Polona Hercog to advance to the quarterfinals at the New Haven Open tennis event on Tuesday.

The top-seeded Dane cruised to a 6-3, 6-0 decision over the Slovenian on a day that earlier saw play suspended for a couple of hours because of an earthquake.

A magnitude 5.8 temblor centered about 40 miles northwest of Richmond, Virginia and was felt from Georgia to Massachusetts, which is where President Barack Obama is vacationing this week, in Martha's Vineyard. Shaking was felt at the White House and all over the East Coast when the quake struck at 1:51 p.m. EDT.

Former world No. 1 Jelena Jankovic was playing an opening-round match when play was suspended. After play resumed, the seventh-seeded Jankovic was upended by Russian Elena Vesnina 6-4, 2-6, 6-4. The 2008 U.S. Open runner-up Jankovic was fresh off her runner-up finish against fellow former No. 1 Maria Sharapova in Cincinnati last week.

Before effects of the quake hit on Day 3, third-seeded French Open runner-up Francesca Schiavone reached the quarterfinals with a 6-2, 6-1 pasting of Romanian Monica Niculescu.

In other second round action, Czech Petra Cetkovska pulled off a marathon 6-4, 5-7, 6-3 upset over fifth-seeded Pole Agnieszka Radwanska in two-hours and twenty-four minutes, and American Christina McHale rolled past Spain's Carla Suarez Navarro with a 6-2, 6-2 victory, winning 32-of-46 service points and converting 5-of-7 break chances.

The top seeds here are world No. 1 and three-time reigning champion Wozniacki and French Open winner and Australian Open runner-up Li Na.

This New Haven event serves as a final hardcourt U.S. Open tuneup.

The 2011 New Haven titlist will earn $103,000.