Big names underwent a tough Saturday at the French Open as fourth seeds Novak Djokovic and Elena Dementieva both bowed out and Roger Federer and Serena Williams rallied from a set down to advance into the fourth round.

Serbia's Novak Djokovic returns the ball against Germany's Philipp Kohlschreiber during the 3rd round competition of men's singles at the French Open tennis tournament at Roland Garros in Paris, France, May 30, 2009. Djokovic lost to Kohlschreiber 4-6, 4-6, 4-6. [Xinhua]

Djokovic's dream of capturing the French Open title evaporated after German 29th seed Philipp Kohlschreiber swept the Serbian aside 6-4, 6-4 and 6-4 in two hours 21 minutes while unfancied Samantha Stosur avenged her 2009 Australian Open loss to women's fourth seed Dementieva in a 6-3, 4-6, 6-1 victory, entering the second week at Roland Garros for the first time.

Federer, bidding for the only Grand Slam title which has eluded him, survived an early niggle before bearing down in windy conditions to dispatch home player Paul-Henri Mathieu 4-6, 6-1, 6-4, 6-4.

Serena was also made sweat as the U.S. and Australian Open champion conquered Maria Jose Martinez Sanchez of Spain 4-6, 6-3, 6-4.

Djokovic, strangely out of sorts, struggled to find his timing all match long, hitting 38 unforced errors and a whole bunch more that were forced upon him by Kohlschreiber's incessant long hitting, both down the line and cross court.

"What is disappointing was that I couldn't find the rhythm throughout the whole match. This is what I was always managing to do," said the 22-year-old.

"I can't really explain why. Physically I felt good, but it's just a bad day at the office. Of course he played very solid," he added.

This is not the first time the German has caused an upset. He knocked Andy Roddick out of the Australian Open last year, but no one really expected him to trouble the Serb, who some had tipped to overthrow current world number one Rafael Nadal this year.

"I think I played really, really one of the best matches I ever play in a big tournament," said Kohlschreiber, who, with the win, equaled his best grand slam showing of two last-16 appearances at the Australian Open.

"Maybe Novak didn't play his best today. But from my point of view ... I did a really good job today."

Switzerland's Roger Federer plays a forehand against French player Paul-Henri Mathieu during the 3rd round competition of men's singles at the French Open tennis tournament at Roland Garros in Paris, France, May 30, 2009. Federer won the match 4-6, 6-1, 6-4, 6-4. [Xinhua]

Federer had beaten his 35th-seeded opponent three times without a loss but lost his way in the opening set. But Mathieu didn't roll over in front of his home public while the 13-time Grand Slam champion dominated the following three sets and took his second match point with an inside-out forehand winner.

Serena added more spice after her ill-tempered win by calling her Spaniard opponent a "cheat".

Their first set featured an incident in which Martinez broke serve to lead 3-2 after a shot appeared to rebound off her arm. The Spaniard won the point and then the set.

"The ball did touch her 100 percent on her arm," Williams said. "The rules of tennis are when the ball hits your body, then it's out of play. The ball hit her body, and therefore, she should have lost the point instead of cheating."

But Martinez refused to accept the label. "I put the racquet up," the 43rd-ranked Spaniard said. "The ball was in and it was a point for me. It didn't hit me or my body. To say I'm a cheat is stupid. I'm not going to comment on it."

Roddick, the only American man left at the tournament, made it into the round of 16 in Paris for the first time in his career by beating Marc Gicquel of France 6-1, 6-4, 6-4.

The sixth seed, who had never made an impression on the red clay, has been in superb touch and will next play French 11th seed Gael Monfils, who beat Austrian Jurgen Melzer 6-2, 4-6, 6-3, 6-1.

Also in women's event, Jelena Jankovic of Serbia and Svetlana Kuznetsova of Russia both eased through in straight sets, beating Jarmila Groth of Australia and Melina Czink of Hungary respectively.