French Jo-Wilfried Tsonga (down) hits a return to Russia's Andrey Kuznetsov
Jo-Wilfried Tsonga survived the weight of home expectations while dangerman Juan Martin Del Potro shrugged off an injury scare before triumphing on Sunday's sweltering first day at Roland Garros.
French fifth seed Tsonga, the highest-ranked player in action, overcame a worrying first set wobble to beat Russian qualifier Andrey Kuznetsov 1-6, 6-3, 6-2, 6-4.
Tsonga, who sparked controversy on the eve of the tournament by claiming that French players had no chance of winning their home Grand Slam, next faces Germany's Cedrik-Marcel Stebbe.
The last Frenchman to win the title in Paris was Yannick Noah in 1983.
"Against such a player, you feel, okay, let's wait for the storm to be over and in half an hour I'll see what's going on," said Tsonga of his opponent, who was the 2009 Wimbledon junior champion, but was making his debut in Paris.
Ninth seed Del Potro, the Argentine who won the 2009 US Open having made the semi-finals here in the same year, saw off Spanish veteran Albert Montanes 6-2, 6-7 (5/7), 6-2, 6-1 in a shade over three hours.
He will tackle France's Edouard Roger-Vasselin for a place in the last 32.
Del Potro, a potential quarter-final opponent of Roger Federer, had beaten Montanes in straight sets on his way to the Estoril title in April.
But he endured a bumpy ride on the Philippe Chatrier Court when his troublesome left knee, which had already been taped, required further strapping at the end of the marathon second set.
The 23-year-old, the only man outside of Novak Djokovic, Rafael Nadal and Federer to win a Grand Slam title in the last seven years, also needed a doctor three games into the second set as the soaring temperatures threatened to take their toll.
"I was struggling a little, but I had some good treatment which allowed me to finish the match," said Del Potro.
"Roland Garros is a physically-demanding tournament. I have to keep that in mind as I am playing well at the moment."
Andy Roddick slumped to a fifth French Open first round defeat in 10 visits when the injury-plagued American lost 6-3, 6-3, 4-6, 6-2 to France's Nicolas Mahut.
Former US Open champion Roddick, who has never got beyond the third round, came into Roland Garros having made his season's European claycourt bow only in Dusseldorf last week where he lost all three matches.
Now ranked at 29 in the world, Roddick has been battling hamstring and hip problems for most of the year.
"Down two sets, it's not where you want to be," said Roddick. "I move horrendously on this stuff, I feel like I am shuffling around. I made a choice to play and I lost."
Also making the last 64 was 2003 champion Juan Carlos Ferrero, who defeated French wildcard Jonathan Dasnieres de Veigy 6-1, 6-4, 6-3.
In the women's event, US Open champion Samantha Stosur had the honour of being the first player into the second round, brushing aside Britain's Elena Baltacha.
The Australian sixth seed, the 2010 runner-up to Francesca Schiavone, took just over an hour to see off the 68th-ranked Baltacha 6-4, 6-0 on Philippe Chatrier court.
Joining Stosur in the next round were former champions, Russia's Svetlana Kuznetsova and Ana Ivanovic of Serbia.
Kuznetsova, the 2009 winner, marked her 40th Grand Slam appearance with a comfortable 6-1, 6-3 win over Croatian world number 117 Mirjana Lucic.
Serbian 13th seed Ivanovic, the 2008 champion, was also a first day winner, cruising past Spain's Lara Arruabarrena-Vecino 6-1, 6-1 in under an hour.
Venus Williams battled back from a set down to defeat Argentine teenager Paula Ormaechea 4-6, 6-1, 6-3.
Williams, seven-times a Grand Slam title winner and runner-up here to sister Serena in 2002, faces either Polish third seed Agnieszka Radwanska or Bojana Jovanovski of Serbia for a place in the third round.
The American is now ranked 53 in the world after battling energy-sapping Sjogren's Syndrome.
World number one Djokovic kicks off his bid for an historic Grand Slam on Monday when he tackles Italian claycourter Potito Starace.
The top seed is just seven wins away from becoming only the third man to hold all four majors at the same time.
Federer, the holder of a record 16 Grand Slam titles, was the champion at Roland Garros in 2009, and he also starts his campaign on Monday against Germany's Tobias Kamke.
Defending champion Rafael Nadal, chasing a seventh French Open, begins on Tuesday against Italy's Simone Bolelli.