Lleyton Hewitt withstood a serving masterclass by Ivo Karlovic to hit back from two sets down and claim an epic first-round win.
Karlovic, who is 6ft 10in tall, powered down 55 aces - which is believed to be a record for a singles match in the Open era - on Court One but still somehow lost, making it 11 successive five-set defeats for the Croatian.
The never-say-die spirit of Hewitt, the former world number one who is on an upward spiral after an injury-hit 2008, was in evidence as he posted a four-hour 6-7 (1/7) 6-7 (4/7) 7-6 (7/4) 6-4 6-3 victory to stay on course for a possible third-round meeting with top seed Rafael Nadal.
Hewitt said: "It's more of a mental battle to come back from two sets after you lose them in breakers.
"You have to hang in there and be prepared to go the distance. That's what I'm proud of today."
Hewitt, who won from two sets down for the fifth time in his career, admitted he was often left helpless by Karlovic's monster serve, adding: "It's frustrating but you have to put it aside.
"You know it's going to happen when you go out on court."
Hewitt, currently ranked 50 in the world, takes on Andrey Golubev of Kazakhstan next.
With third seed Andy Murray routing Argentina's Juan Ignacio Chela 6-2 6-2 6-1, the biggest casualty of the day looked like being a home favourite, Gilles Simon.
The seventh seed had major trouble dealing with his opponent from the United States, Wayne Odesnik, and it was nip and tuck until Simon finally eased away in the fifth set to seal a 3-6 7-5 6-2 4-6 6-3 triumph. He will next play another American, Robert Kendrick.
Eighth seed Fernando Verdasco wasted little time in brushing aside Florent Serra in straight sets to reach the second round.
The Spaniard, who lost to Nadal in an epic Australian Open semi-final earlier this year, was in impressive form as he won 6-2 6-1 6-4.
Verdasco has had a solid 2009, making the quarter-finals of all eight of the tournaments he has played in, but he acknowledges he has a tough draw at this event.
"It's going to be difficult but I'll see if I can make the quarter-finals to play Rafa (Nadal) - I'll take that," said Verdasco, who may have to get past Nicolas Almagro and Nikolay Davydenko before that.
David Ferrer, a compatriot of Verdasco and the 14th seed here, encountered few problems in his 6-2 6-4 6-4 success over Frederico Gil while 18th seed Radek Stepanek was also a comfortable straight-sets winner, beating 2004 champion Gaston Gaudio 6-3 6-4 6-1.
Earlier, Marat Safin, the 20th seed and, like Hewitt, a two-time grand-slam champion, launched his final Roland Garros campaign with a 6-4 6-4 6-4 victory over Frenchman Alexandre Sidorenko.
"If I have a couple more matches here, it would be great," said Safin, who is retiring at the end of the year.
"I'm not really happy with the way I played but the result was okay."
It was only the Russian's second win on clay in his farewell season and he will next play France's Josselin Ouanna, a winner in four sets against Marcel Granollers.
Croatia's Marin Cilic, the 13th seed, lost only seven games as he cruised past Jan Hernych 6-0 6-4 6-3 and 31st seed Almagro crushed Agustin Calleri 6-4 6-1 6-3.
Elsewhere, there were wins for Dudi Sela, Philipp Petzschner and French lucky loser Mathieu Montcourt, who progressed after opponent Yen-Hsun Lu retired injured.
Meanwhile, France's Gael Monfils, the 11th seed, confirmed at a press conference he will be fit to play Bobby Reynolds in his first-round match on Tuesday even though he is suffering with a knee injury.