Updated

Former champions Caroline Wozniacki and Sam Stosur were a pair of easy second-round winners Wednesday at the Family Circle Cup tennis event.

The second-seeded Wozniacki, who only entered this tournament Saturday when a scheduled trip to Haiti with boyfriend Rory McIlroy was postponed, blew past Spaniard Silvia Soler-Espinosa 6-1, 6-1 in a mere 59 minutes, while the third- seeded former U.S. Open titlist Stosur whipped New Zealand's Marina Erakovic 6-1, 6-2 on the green clay at Daniel Island Tennis Center.

Wozniacki was the big winner here two years ago, while Stosur was the 2010 Charleston champ.

"I felt like I really served well and returned well today," Wozniacki said after pasting Soler-Espinosa. "I'm pleased with that."

Meanwhile, American qualifier Mallory Burdette pulled off an upset by dismissing 15th-seeded 2009 champion Sabine Lisicki 3-6, 7-6 (7-5), 7-5. Burdette is rewarded with a match against world No. 1 superstar and reigning Charleston champ Serena Williams.

In some other second-round action involving seeds, No. 10 Julia Goerges of Germany held off Belarusian Olga Govortsova 6-2, 0-6, 6-3 and Canadian qualifier Eugenie Bouchard upended No. 16 Brit Laura Robson 6-4, 3-6, 6-1. Bouchard will face Stosur on Day 4.

Promising American Madison Keys eased into the round of 16 with a 6-4, 6-3 handling of qualifier compatriot Grace Min. Keys will battle another fellow American, wild card Bethanie Mattek-Sands, on Thursday.

The winner of this $795,000 tournament will earn $125,000.