Defending champion Roger Federer sheltered from soaring temperatures at the French Open on Sunday and watched as two pretenders to his title toiled in the Roland Garros sweatshop.
French eighth seed Jo-Wilfried Tsonga needed five sets to see off dangerous German Daniel Brands, but Ernests Gulbis, who defeated world number one Federer in Rome, and was regarded as a dangerous outsider here, limped to defeat.
The Latvian 23rd seed, who also took Rafael Nadal to three sets in the Rome semi-finals, suffered a hamstring injury and retired against France's Julien Benneteau in his first round match.
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"I stretched my hamstring in my right leg and I heard two cracks. I will go for a scan and hope that nothing is broken," said 21-year-old Gulbis, who was trailing 6-4, 6-2, 1-0 when he called it quits.
"It's very disappointing. I prepared really well for the tournament. But I have another eight or nine years in front of me, maybe 20 Grand Slams.
"If I concentrate on just this one, I'd go nuts."
Tsonga, bidding to become France's first men's champion since 1983, saw off world 89 Brands 4-6, 6-3, 6-2, 6-7 (2/7), 7-5, but needed three match points and almost four hours.
He will meet compatriot Josselin Ouana for a place in the last 32.
"My opponent played well. He served really well and I wasn't at the top of my game," said Tsonga, who has been laid low recently by a bad back and was a break down in the final set.
Elsewhere, Alejandro Falla of Colombia beat Serbia's Janko Tipsarevic 6-1, 6-2, 6-3 and will face Federer in the next round.
Swedish fifth seed Robin Soderling, last year's runner-up to Federer after sending four-time champion Nadal to a first career defeat here, cruised to a 6-0, 6-2, 6-3 win over France's Laurent Recouderc.
Women's event
In the women's event, defending champion Svetlana Kuznetsova reeled off 11 of the last 12 games to move into the second round with a 6-3, 6-1 win against Romania's Sorana Cirstea.
But 10th seeded Belarusian Victoria Azarenka, a quarter-finalist in 2009, and Spanish 20th seed Maria Jose Martinez Sanchez, the shock winner in Rome last month, both saw their campaigns end on the opening day.
Kuznetsova, the Russian sixth seed, will now face Germany's Andrea Petkovic, who beat Elena Vesnina 4-6, 6-1, 6-4.
"I was not showing the good results I would have liked to, but I knew this moment has to pass because I deserve better than that," said Kuznetsova who won just one claycourt match coming into Paris.
Azarenka, whose recent form has been affected by a series of thigh and groin injuries, slipped to a 6-1, 6-2 defeat at the hands of Argentina's Gisela Dulko.
Martinez Sanchez, meanwhile, went down 6-2, 6-4 to Uzbekistan's world 97 Akgul Amanmuradova, as the form which took her to wins over top 10 players Caroline Wozniacki and Jelena Jankovic in Rome deserted her.
Second seeded American Venus Williams defeated Patty Schynder 6-3, 6-3 to notch up her 11th win over the Swiss veteran in 11 meetings.
Williams, the 2002 runner-up to sister Serena, will next face either Japanese qualifier Kurumi Nara or Spain's Arantxa Parra Santonja.
"My record against her (Schnyder) definitely helped me, especially in tighter situations," said Williams, who took victory on a fourth match point, having double-faulted on the first against a player making her 15th consecutive Roland Garros appearance.
Slovakia's 26th seed Dominika Cibulkova, a semi-finalist in 2009, edged Russia's Ekaterina Ivanova 6-2, 6-0 while South African qualifier Chanelle Scheepers reached the second round of a Grand Slam for the first time when she defeated France's Mathilde Johansson 6-2, 6-4.
