Shenzhen, China (SportsNetwork.com) - Top seeds Simona Halep and Petra Kvitova won their season-opening matches Monday at the Shenzhen Open tennis tournament.

The world No. 3 French Open runner-up Halep came back to beat German Annika Beck 4-6, 6-4, 6-3, while the left-handed Wimbledon champion and fourth-ranked Kvitova clipped Chinese wild card Duan Ying-Ying 6-3, 6-1 on the hardcourts at Shenzhen Loonggang Tennis Centre.

A bevy of upsets occurred when former Wimbledon runner-up Vera Zvonareva took out third-seeded Chinese favorite Peng Shuai 4-6, 6-4, 6-3, Czech Katerina Siniakova bested sixth-seeded Romanian Irina-Camelia Begu 6-7 (5-7), 6-4, 6-1 and Slovenian Polona Hercog handled seventh-seeded Romanian Monica Niculescu 6-1, 7-5.

Li Na beat Peng in last year's all-Chinese finale.

Some other opening-round wins came for Italian Karin Knapp and Serbian Bojana Jovanovski, who should have her hands full with Kvitova in a second-round affair here on Tuesday.

Shenzhen serves as a tune-up for the Australian Open, which will begin January 19 in Melbourne.