Three-time world champion Maurice Greene eased through his opening heat in his bid for an unprecedented fourth consecutive 100 metres title.
World record holder Tim Montgomery brushed aside worries over his recent poor form and made a statement of intent by clocking 10.07 seconds, the second fastest of the 10 heats.
There were no surprise exits with the leading protagonists for what is a wide open event taking the opportunity to stretch their legs, including European champion Dwain Chambers.
Greene, the dominant sprinter of his era, clocked 9.94 in California in June but has struggled with tendinitis in his right leg which has affected his consistency.
He did not make the best start on Sunday but a late surge was enough for second place behind Ghana's Eric Nkansah. Both sprinters were timed at 10.18.
Greene, asked if he was in good shape, replied "of course" as he left the track at the Stade de France.
THE PEANUTS
Fellow-American Montgomery, who has blamed his poor form on a peanut allergy that affected his immune system, was quick out of the blocks and won his heat in a time just outside his season's best.
Asked if he was looking good, he replied: "You've got that right. He then joked: "It's the peanuts."
Chambers, who has a strong chance of becoming the first Briton to take the world title since Linford Christie in 1993, cruised through in a slow heat.
He clocked 10.33 to follow home Matthew Shirvington of Australia, but the Englishman barely broke sweat.
Bernard Williams, U.S. champion and 2001 world bronze medallist, also eased into the second round in 10.19 while Jamaican Asafa Powell had the round's quickest time of 10.05.
Australia's Patrick Johnson, who has the leading time in the world this year -- 9.93 in Mito in Japan in May -- won his heat in a pedestrian 10.29.
The second round takes place later on Sunday with the semi-finals and final on Monday.
