's-Hertogenbosch, The Netherlands (Sports Network) - Italian stars Roberta Vinci and Francesca Schiavone were a pair of second-round winners Wednesday at the $220,000 UNICEF Open, a final Wimbledon tune-up.

The sixth-seeded reigning Den Bosch champion Vinci held Romanian Monica Niculescu 6-3, 6-7 (4-7), 6-0, while the former French Open titlist Schiavone outlasted Romania's Irina-Camelia Begu 6-2, 2-6, 7-6 (10-8) on the grass courts at Autotron Rosmalen. Schiavone is rewarded with a quarterfinal bout against unseeded former world No. 1 Kim Clijsters, the four-time Grand Slam champ who captured this Dutch event in 2003 and was the runner-up in 2001.

Vinci, who beat Aussie Jelena Dokic in last year's UNICEF finale, will face Belgian Kirsten Flipkens on Thursday. The qualifier Flipkens stunned top seed and U.S. Open champion Sam Stosur here on Monday.

In other second-round play on Day 4, Flipkens defeated Russian qualifier Daria Gavrilova 7-5, 7-6 (7-4) and Swede Sofia Arvidsson handled Dutch wild card Arantxa Rus 6-4, 6-1.

The other quarters will pit third-seeded Slovak Dominika Cibulkova against eighth-seeded Russian Nadia Petrova and Arvidsson versus Poland's Urszula Radwanska.

The 2012 champion here will collect $37,000.