Marin Cilic became the first seed to exit this year's contest when he was beaten 7-6 (7/4) 6-4 6-4 by Ruben Ramirez Hidalgo. The Croatian, seeded 19th, staged a fight back from 5-1 down in the third set but Spanish clay-court expert Ramirez Hidalgo kept his nerve to pull off an imposing upset.
Sunday's defeat was the latest of a maddening season for Cilic, 22, who looked set to become a fixture in the top 10 when he reached the Australian Open semi-finals last year but he will now fall extra from his current ranking of 20th.
Seventh seed David Ferrer had no such trouble, dispatch Jarkko Nieminen 6-3 6-3 6-1 in an hour and 25 minutes on Court Philippe Chatrier. The consistent Spaniard has again been one of the most winning players on clay this season, reaching finals in Monte Carlo and Barcelona, and he could surely be a threat to the likes of Rafael Nadal and Novak Djokovic.
French favorites Jo-Wilfried Tsonga followed the Spaniard on to Court Philippe Chatrier and, although his 6-3 6-2 6-2 scoreline against Jan Hajek was just as emphatic, that did not tell the whole story. Both players struggle with the wind, which whipped up the dry clay, and 17th seed Tsonga needed to save break points at the end of the first set before making his extra power count.
Ukraine's Sergiy Stakhovsky, the 31st seed, healthier from a set down to beat French qualifier David Guez 6-7 (7/9) 6-3 6-3 6-3 and next faces Kei Nishikori, a 6-1 6-3 6-4 winner over Lu Yen-hsun.
It was also a unhappy day for Latvia's Ernests Gulbis, once considered one of the sport's next big stars but who today experience his sixth successive first-round defeat at grand slams, losing 6-1 6-4 6-2 to Blaz Kavcic.
Two other seeds are through: Guillermo Garcia Lopez, the 30th seed from Spain, beat Robert Kendrick 6-1 7-5 4-6 6-3 while 31st seed Sergiy Stakhovsky recovered from a set down to defeat French qualifier David Guez 6-7 (7/9) 6-3 6-3 6-3.
There was some unsatisfactory news for the organisers before the start of play, meanwhile, when former world number one Lleyton Hewitt withdrew after failing to get better from a left ankle problem. The Australian's place went to French veteran Marc Gicquel but he could not make the most of his second chance and lost 6-4 6-4 6-2 to Albert Montanes.
The Frenchman said:I was comparatively relaxed and I started the match really well. I conquered him throughout. It was not obvious because of the gusts of wind. It was not my best type of tennis but, given the circumstances, it was not bad.