Azarenka marches on in Doha

Victoria Azarenka made it safely through to the third round of the Qatar Open as the seeds were untroubled in Doha.

World number one Azarenka is playing to stay at the top of the rankings this week, with Serena Williams and Maria Sharapova in pursuit. Williams will go to number one should she reach the semi-finals, irrespective of what Azarenka achieves.

But all the Belarusian can do is focus on her own game, which a 6-2 6-3 victory over Switzerland's Romina Oprandi suggested was in good shape.

Azarenka is playing on tour for the first time this week since successfully defending her Australian Open title in Melbourne last month, and is the top seed.

Fourth seed Agnieszka Radwanska had a similarly comfortable ride through to the last 16, the Pole defeating Australian Anastasia Rodionova 6-3 6-2.

Italian sixth seed Sara Errani eased to a 6-4 6-0 success against Hungary's Timea Babos, and seventh-seeded Czech Petra Kvitova toppled Russian Ekaterina Makarova without needing to play a second set.

The 2011 Wimbledon champion took the opener 6-4 before Makarova retired hurt.

Serbian Ana Ivanovic also benefited from an injured opponent, with the 13th seed taking the first set 6-3 against Romanian Simona Halep who then called time on their match. Ivanovic will face Radwanska next.

Nadia Petrova had to grind out a second-round win, the 11th seed from Russia pushed hard by Taipei's Hsieh Su-Wei before coming through 3-6 6-2 6-4 to set up a tussle with Kvitova.

Twenty-year-old unseeded American Christina McHale produced an impressive victory, eliminating Czech 17th seed Lucie Safarova 6-4 6-2. She faces Azarenka in a daunting match next.

McHale has a win by her name from their only previous meeting, three years ago in Charleston, but it came rather by default after Azarenka, leading by a set, retired due to injury.

Former world number one Caroline Wozniacki, seeded 10th here, was a straight sets winner over Romania's Sorana Cirstea.

Wozniacki won 7-6(7) 6-0 in an hour and 23 minutes and book a meeting with Mona Barthel.

Eighth seed Samantha Stosur was taken to a deciding third set by Monica

Niculescu, but eventually prevailed 6-4 1-6 6-3.

Svetlana Kuznetsova sent ninth seed Mario Bartoli packing 6-4 6-4, while

Daniela Hantuchova defeated Ekaterina Bychkova 6-3 1-6 6-3.

Klara Zakopalova lost the first set to Sloane Stephens 4-6 but hit back to take

the next two on tie-break to complete the third-round card.