Wimbledon champion Petra Kvitova was among the top three women's seeds to fall in the first round of the Eastbourne Championships on Tuesday.

However, defending champ Marion Bartoli of France beat Sorana Cirstea of Romania 6-2, 6-2. American Christina McHale upset third-seeded Caroline Wozniacki 6-1, 6-7 (4), 6-4.

In the men's event, Andy Roddick claimed his first win in seven matches when fellow American Sam Querrey retired with an injury with Roddick leading 5-2.

Yen-hsun Lu of Taiwan beat fifth-seeded Julien Benneteau of France 6-3, 2-6, 7-6 (4). Kivitova was the first to exit, going down 7-5, 6-4 to Ekaterina Makarova of Russia 7-5, 6-4.

She was followed out of the grass-court tournament by top-seeded Agnieszka Radwanska of Poland, who fell 6-2, 6-4 to Tsvetana Pironkova of Bulgaria.

"It was a tough opponent for me for the first round, and I didn't play well," Kvitova said. "She has won here in the past, so I know that she can play well on the grass. For me, this was my first match on grass and I didn't expect too much."

Wozniacki always looked uncomfortable against the big-hitting McHale.

After splitting the first two sets, McHale broke to lead 2-1 in the third. Although she allowed Wozniacki to level at 4-4, the American broke serve again at love and closed out the match on her fourth match point.

The second-seeded Kvitova put on an erratic performance during her first match on grass since lifting the trophy at Wimbledon last year.

"It's not good preparation for Wimbledon, but I have more days for getting ready. I have to work hard now to improve my game," Kvitova said.

Radwanska has enjoyed a spectacular season, winning titles in Dubai, Miami and Brussels, and she believes that may have taken its toll.

"I think I have been playing a lot of matches this year, and I'm kind of like a little bit tired," said Radwanska, who double-faulted on match point. "Of course I was trying everything, but she's really playing good on grass."