French Open: Wimbledon Champion Petra Kvitova Finds Form

Wimbledon champion Petra Kvitova powered into the last 16 at the French Open on Saturday, finally finding her form after earlier struggles at Roland Garros.

The fourth seed from the Czech Republic outplayed Romanian Irina-Camelia Begu 6-3, 6-2 in just 58 minutes, taking the last five games at a canter.

That was in stark contrast to her first two rounds that saw her grind out six sets and spend just four minutes short of five hours on the court.

"I think it was for sure the best match which I played here so far, so I'm really glad for it," Kvitova said.

"I'm glad that I didn't forget many things from my game and it's still there. I felt better today, for sure. It's the third round which I didn't pass here last year, so I was really motivated by it."

Next up for Kvitova, who also won Wimbledon in 2011, but who has only managed a single semi-final in Paris in 2012, will be a fourth round tie against Timea Bacsinszky of Switzerland who upset 16th seeded American Madison Keys 6-4, 6-2.

Also through to the last 16 in early play was Italian Sara Errani, losing finalist in 2012, who gained revenge on Andrea Petkovic of Germany 6-3, 6-3.

Petkovic ousted Errani at Roland Garros last year at the quarter-final stage before losing in the semis.

There was disappointment though for another Italian, 2010 Roland Garros champion Francesca Schiavone losing 7-5, 6-4 to Andreea Mitu of Romania.

Ranked 100th in the world, Mitu is playing in her first French Open and her three wins in Paris this week were her first at Grand Slam level.

Her next opponent, with a quarter-final slot at stake will be 93rd-ranked Alison Van Uytvanck of Belgium, who ended the hopes of France's Kristina Mladenovic 6-4, 6-1.

Van Uytvanck was 1-5 in Grand Slam matches coming into Roland Garros, but like Mitu she has been able to benefit in her quarter of the draw from the first round defeat of sixth seed Eugenie Bouchard at the hands of Mladenovic.

"It was not easy because she is a very good player and I was very nervous in the beginning," said Van Uytvanck.

"It's a big dream come true. I was happy enough winning in the first round and now being in the fourth round I can't believe it.

"Maybe I am the favourite in the fourth round. I think she (Mitu) is very confident. She's a solid player. She is a big hitter. We have nothing to lose."

Saturday's action at Roland Garros, completing the last 16 lineup for the women, saw four American players in action led by top seed and two-time winner Serena Williams.

The bottom half of the draw completed third round matches on Friday giving an all-European lineup headed by second seed and defending champion Maria Sharapova of Russia.

Williams was scheduled last on the Court Philippe Chatrier, going up against back-to-form Victoria Azarenka of Belarus.

The two have played each other 18 times with Williams well ahead at 15-3, but the 19-time Grand Slam winner looked out of sorts in the second round, needing three tough sets to see off the challenge of unheralded German Anna-Lena Friedsam.

The defeat of Keys though was followed by Irina Falconi's 6-1, 6-4 loss to Julia Goerges of Germany, leaving just Williams and fit-again Sloane Stephens, who was playing Tsvetana Pironkova of Bulgaria later in the day.