SYDNEY — Top-ranked Serena Williams opened her season with a 6-1, 6-2 win over Maria Jose Martinez Sanchez on Tuesday, reaching the quarterfinals at a Sydney International where other leading players have struggled.

No. 3 Svetlana Kuznetsova lost 7-5, 6-2 to Slovakia’s Dominika Cibulkova later Tuesday, joining fourth-seeded Caroline Wozniacki, No. 7 Jelena Jankovic and No. 8 Vera Zvonareva as losers in the first two rounds.
Second-seeded Dinara Safina was in trouble in her first set since she quit with a back injury at the season-ending championships in October, losing the opening five games before recovering to win nine straight in a 7-5, 6-4 victory over Agnieszka Radwanska of Poland.
Safina will next play Olympic gold medalist Elena Dementieva, who held off Slovakia’s Daniela Hantuchova 6-2, 4-6, 6-2.
Sixth-seeded Victoria Azarenka of Belarus beat Japanese veteran Kimiko Date Krumm 6-1, 5-7, 7-5.
Elena Vesnina, who advanced from the first round when Zvonareva retired hurt on Monday, lost 6-3, 6-4 on Tuesday to Vera Dushevina, who plays Williams in the quarterfinals.
Williams said she wasn’t bothered about how many seeded players made early exits, or how it opened up the draw for her.
“I don’t care who I play. Whenever I play someone they play their best.” she said. “I play Vera Dushevina next and she’s a good player and she’s been ranked high before.
“So whoever I play, believe me, they’re going to play like No. 1 on that particular day against me for whatever reason, so it doesn’t matter for me.”
Williams is using the Sydney tournament as her main warmup for the first major of the season, which starts next Monday in Melbourne.
She won the WTA Championship on Nov. 1 and had a bye in the first round here. She spent only 1 hour, 12 minutes on court against Spanish Hopman Cup winner Martinez Sanchez as temperatures hit 91 degrees.
Williams said she wanted to play matches to acclimatize quickly, with the southern city of Melbourne experiencing a heatwave a week ahead of the Australian Open.
Safina spent 1:47 on court and dropped serve five times in a struggle against No. 10-ranked Radwanska. Despite the slow start, she said the back inflammation which restricted her training until the middle of last month didn’t cause her any concerns in Sydney.
“I was 5-love down, but the only problem was I was missing everything — everything was flying all over the place,” Safina said. “So once I win a game, I’m like, ’OK, let’s start like this.
“Once it clicked, it started to be better.”
Safina, a finalist here last year and at the Australian Open, saved a set point in the first before breaking Radwanska in the match-turning 10th game and was satisfied with her comeback.
“I mean, it’s the first match of the year. If you start to cry in the first game of first match, then what can happen when it’s going to be the end of the season,” she said. “It was 20 minutes and 5-love. I thought, ’OK, at least try to stay a little bit longer on the court.”
Kuznetsova was unable to play at leadup tournaments in Brisbane or Auckland last week because she didn’t fulfill her quota of tournaments in 2009 under the WTA’s regulations for top player commitments, so she’ll go to the Australian Open with one match for preparation.
The reigning French Open champion said she’d been playing well in training and hoped to pick up rhythm in practice at Melbourne Park this week and in the early stages of the Australian Open.
“To play good here it would be nice. But if I didn’t, I mean, it’s not so bad thing,” she said. “Definitely I’m very worried about match today, and I have to improve and practice a lot before Australian Open, but that’s not the worst thing in the world.”
In men’s first-round matches, sixth-seeded Viktor Troicki of Serbia advanced over Frenchman Florent Serra 7-6 (5), 6-4, No. 8 Benjamin Becker had a 6-3, 6-3 win over Juan Ignacio Chela of Argentina, and American Mardy Fish beat Australia’s Carsten Ball 6-4, 7-6 (4).
American Sam Querrey, seeded fifth, lost 6-2, 5-7, 6-4 to Russia’s Evgeny Korolev.