BEIJING (AFP) - Russia's Dinara Safina and Svetlana Kuznetsova struggled to find their rhythm but advanced Sunday to the second round of the China Open, as many of the world's top women players were in action in Beijing.

Safina, the top seed looking to bounce back after an embarrassing loss last week in Japan to an unknown teenage Taiwanese qualifier, defeated Italy's Roberta Vinci in straight sets, 6-4, 6-4, but it did not look easy.

The pair traded breaks throughout the match, with Safina losing her serve four times and the 26-year-old Vinci surrendering hers six times.

The 23-year-old Russian, who is looking to keep world number two Serena Williams from overtaking her in the world rankings, will face Chinese wild card Zhang Shuai in the second round.

Safina said ahead of Sunday's match that she had taken a few days off after her loss in Tokyo to Taiwan's Chang Kai-chen, ranked a lowly 132 in the world, in order to regain her competitive edge.

"Sometimes it makes no sense to go back on the court and work even harder, but it?s better to step back, take a breath and relax. That?s what I did" to prepare for Beijing, she told reporters.

Kuznetsova, the tournament's sixth seed and reigning French Open champion, survived a scare from China's Zheng Jie, falling behind early in both sets but outlasting her opponent 7-6 (7/3), 7-5.

The 24-year-old Russian -- who is ranked sixth in the world but also crashed out early in Tokyo -- was on the ropes in the first set against world number 32 Zheng, losing her first service game and quickly falling behind 0-3.

But Kuznetsova, who won the China Open in 2006, rallied with powerful ground stroke winners to pull even at 3-3 and Zheng, clearly the crowd favourite, came up short in the first set tiebreak, surrendering the set on an unforced error.

The 26-year-old Chengdu native, who had never beaten Kuznetsova in four previous meetings, again went up early in the second set, but the Russian veteran showed perseverance to close out the match in straight sets.

"I think that I started both sets pretty slow. I wasn?t quite moving well," Kuznetsova said after the match.

"Then when I started to move better, I started to play better. Then I lost my concentration again, and then got it back and started to play better."

Williams' centre court battle against Estonia's Kaia Kanepi was under way.

Russia's Elena Dementieva, the fourth seed, and number five Caroline Wozniacki of Denmark were also due on court later Sunday.

Third seed Venus Williams of the United States advanced to the second round on Saturday.

In other first round matches on Sunday, Russian seventh seed Vera Zvonareva beat Romania's Sorana Cirstea 6-2, 6-2, and Switzerland's Patty Schnyder got past Poland's Urszula Radwanska 6-4, 7-5.

Ninth seed Victoria Azarenka of Belarus advanced, easily defeating compatriot Olga Govortsova 6-1, 6-3.

The men's main draw gets under way on Monday, with Rafael Nadal, Novak Djokovic and Andy Roddick leading the charge.