BEIJING, China - Svetlana Kuznetsova's up-and-down season took one of its downturns on Sunday, as the former No.2 - now ranked No.13 in the world - fell in the first round of her title defense at the $4.5-million China Open.

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Kuznetsova, who beat Agnieszka Radwanska for last year's title and was seeded No.10 this year, showed her best tennis in the second set but couldn't keep her level up in the third, losing out to qualifer Roberta Vinci, 63 26 63.

"It took me some time to get used to her game, the court, the wind. I started playing well in the second set," Kuznetsova said. "I didn't take my chances in the third set. It was equal in the third, 1-all, 2-all, 3-all... then I lost the break."

Kuznetsova was bothered after the US Open by a bout of the flu; she lost in the second round of last week's Toray Pan Pacific Open. "After US Open I practiced hard for a week in Moscow. I was supposed to leave on Tuesday for Tokyo so I'd have five days to practice and everything," Kuznetsova added. "I got sick. From Sunday to Saturday, one week, I wasn't home, I didn't go out, I didn't do any fitness, I was in bed. I didn't have time, but that's how it is."

There were mixed results for the other seeds in action on Day 2, with No.4 seed Sam Stosur, No.14 seed Aravane Rezai and No.16 seed Anastasia Pavlyuchenkova all falling as well, but No.9 seed Li Na, No.12 seed Maria Sharapova and No.13 seed Nadia Petrova all making the second round.

Read more about Stosur and Sharapova's matches right here.

Li, China's No.1, took just 58 minutes to beat Alla Kudryavtseva, 62 60. Kudryavtseva recently won her first Sony Ericsson WTA Tour title in Tashkent.

Maria Kirilenko, Alisa Kleybanova, Dominika Cibulkova, Petra Kvitova, Polona Hercog and qualifier Bojana Jovanovski also scored wins.

Kleybanova next faces Li. "She's a great player," the Russian said. "She has been playing very well this year and had some good results in the Grand Slams. It will be interesting to play her. She will have all the support from the crowd. I'm really looking forward to it. It will be our first meeting and a good challenge."