The win over Simon was more difficult than his victory over Frenchman Julien Benneteau in the third round. The crowd gave Simon an ovation when he trudged off centre court, but there seemed to be an air of relief that Federer had stayed on course to repeat his 2009 French Open win.

That was evident in the sixth game of the fourth set, when he turned potential defeat into victory by breaking Simon for a 4-2 lead, and in the fifth set when he broke for a 2-0 lead.

"Of course I would like to have had more support," Simon said. "If I don't get it here, I won't ever get it."

Federer's popularity at Roland Garros is so great that Frenchman Tsonga will probably not have unanimous support when he takes on the Swiss star.

Tsonga trails Federer 9-3 in their matches. He has beaten him in a grand slam, when he rallied from two sets down to win their 2011 Wimbledon quarter-final, but Federer won their three other meetings in majors, twice at the Australian Open, once at the US Open.

"I won't be taking him on any differently to how I have taken him on in the past," Federer said. "He's a very good player, Tsonga. He's dangerous, dangerous for everybody ranked in the top four in the world. He's proved his worth in the past."

Federer was in danger of his earliest exit from a grand slam tournament in nine years - but ended up writing another line in the history books, despite twisting his right foot awkwardly.

"It wasn't because of the fall that I started losing," Federer said. "It was really because of the quality of Gilles' game."

It was Federer's 58th win in his French Open career, against 13 losses, equalling the mark for most wins at the tournament held by Guillermo Vilas and Nicola Pietrangeli. It also was his 900th career victory, which puts him fourth in men's tour history, behind only Jimmy Connors, Ivan Lendl and Vilas.

"I'm not too tired right now. Still fairly fresh," Federer said. "I think I did really well."