Djokovic offers no excuses

The Serbian was upset 6-4 6-4 6-4 by the 29th seed, who has never previously progressed past round two at Roland Garros. Djokovic was installed by many as second favourite for the title, behind reigning four-time champion Rafael Nadal, given his impressive clay-court campaign this year, but was punished for an error-prone display on Court One.

The 22-year-old dubbed it "a bad day at the office", insisting tiredness was not a factor in his defeat. "I was too passive and he played really solid. You have to give him credit for playing tactically smart. Unfortunately I had no solutions," he said.

Djokovic, who played in four of the six tournaments prior to Roland Garros, added: "Mentally I'm a little bit exhausted but that's still not an explanation for my loss. I'm one of the favourites to get far in the tournament. This cannot happen."

Second seed Roger Federer was also in trouble early in his third round match but managed to turn things around to claim a 4-6 6-1 6-4 6-4 over Frenchman Paul-Henri Mathieu.

It was the second successive match in which Federer was taken to four sets, following on from his distinctly unimpressive display in his win over Jose Acasuso.

The Swiss recovered well, though, and can prepare for a last-16 clash with unseeded German Tommy Haas, a 7-5 6-3 4-6 6-4 winner over another Frenchman, Jeremy Chardy.

Andy Roddick had earlier put his Roland Garros demons behind him to finally make the fourth round. The sixth seed posted a 6-1 6-4 6-4 victory over Frenchman Marc Gicquel on Suzanne Lenglen court to continue his terrific streak this week.

Gael Monfils, the 11th seed and a semi-finalist here last year, will be Roddick's next opponent after the Frenchman beat Jurgen Melzer 6-2 4-6 6-3 6-1.

Fifth seed Juan Martin del Potro advanced into the last 16 with an impressive straight-sets victory over Igor Andreev. Away from the showcourts again, Del Potro secured a 6-4 7-5 6-4 win on Court Two and will play ninth seed Jo-Wilfried Tsonga next.