Doha, Qatar (Sports Network) - Top-seeded and defending champion Victoria Azarenka and Wimbledon runner-up Agnieszka Radwanska were a pair of second- round winners Wednesday at the $2.369 million Qatar Open.

The world No. 1 and reigning two-time Australian Open titlist Azarenka blew past Swiss Romina Oprandi 6-2, 6-3 in her first match of the week, while a fourth-seeded Radwanska routed Aussie qualifier Anastasia Rodionova 6-3, 6-2 on the hardcourts at Khalifa International Tennis Complex.

Azarenka beat former U.S. Open champion Sam Stosur in last year's Doha finale.

Up next for Azarenka will be American Christina McHale, while Radwanska will face former world No. 1 and former French Open champ Ana Ivanovic on Thursday. The 13th-seeded Ivanovic was leading Simona Halep 6-3 when the Romanian retired, while McHale upset 17th-seeded Czech Lucie Safarova 6-4, 6-2.

Meanwhile, sixth-seeded French Open runner-up Sara Errani humbled Hungarian Timea Babos 6-4, 6-0, seventh-seeded former Wimbledon winner Petra Kvitova moved past Russian Ekaterina Makarova 6-4, retired, and 10th-seeded former No. 1 Caroline Wozniacki bested Romanian Sorana Cirstea 7-6 (9-7), 6-0. The 2011 Qatar Open runner-up Wozniacki will face rising German Mona Barthel, who titled in Paris two weeks ago, on Thursday.

In other second-round action involving seeds, No. 11 Nadia Petrova overcame Taiwan's Su-Wei Hsieh 3-6, 6-2, 6-4, Urszula Radwanska upended No. 15 Roberta Vinci 6-2, 5-7, 6-0, and Klara Zakopalova ousted No. 16 American Sloane Stephens 4-6, 7-6 (7-5), 7-6 (7-5). Petrova captured the Qatar Open back in 2006. Radwanska, the younger sister of Agnieszka Radwanska, will battle second-seeded former world No. 1 Serena Williams on Thursday, while Zakopalova is rewarded with a match against French Open champion and two-time Doha titlist Maria Sharapova.

Another result saw Slovakian veteran Daniela Hantuchova hold off Russian qualifier Ekaterina Bychkova 6-3, 1-6, 6-3.

The 2013 Qatar Open winner will claim $426,000.

The Sports Network