Rafael Nadal continued his serene progress towards a record seventh men's French Open title with another straight-sets win in the day's final match on Philippe Chatrier Court on Saturday.
The Spanish defending champion defeated good-humoured Argentine qualifier Eduardo Schwank 6-1 6-3 6-4 in two hours 16 minutes.
Nadal, who celebrates his 26th birthday on Sunday, will play either another Argentine, 13th seed Juan Monaco, or Canada's 19th seed Milos Raonic in the last 16.
On a hot day at Roland Garros, Russian Mikhail Youzhny melted hearts when he scrawled the word "SORRY!" in the clay with the toe of his shoe after winning only six points in the first eight games of a three-set thrashing by Spanish sixth seed David Ferrer.
"I just wanted to say sorry to the fans because they came to see a beautiful match but I simply could not give them that," Youzhny told Russian reporters after the 6-0 6-2 6-2 defeat.
Fourth seed Andy Murray, who came close to withdrawing from his second-round match with a back problem on Thursday, looked a new man when he easily beat Colombia's Santiago Giraldo 6-3 6-4 6-4 to reach the last 16.
The Briton will now play 17th seed Richard Gasquet, who beat 34-year-old German Tommy Haas - a qualifier here - 6-7 6-3 6-0 6-0.
Murray said he had felt better on Friday and had done some light practice.
"I woke up this morning again feeling better than I did, but that's because of the work my physio has done the last 48 hours and all the recovery work that we've done between the last match and now," he told a news conference.
"So obviously with the rest and doing all the right things, I felt better."
|A relieved Varvara Lepchenko celebrates her win against 2010 winner Francesca Schiavone [EPA]
Last year's finalists Francesca Schiavone and Li Na headed in opposite directions when the Italian was knocked out in the third round and the Chinese fought her way through to the last 16 with a tough win.
Schiavone, the Roland Garros winner in 2010 and runner-up to Li last year, was unlucky to run into battling American Varvara Lepchenko for the second time in a month.
Lepchenko, who beat the world number 12 on Madrid's new blue clay four weeks ago, struck again, defeating Schiavone 3-6 6-3 8-6 in the midday sun on Court One.
Seventh seed Li had to fight hard against world number 36 Christina McHale of the United States before winning 3-6 6-2 6-1 and setting up a fourth-round match against Kazakh qualifier Yaroslava Schedova.
While her rivals for the women's title toiled, second seed Maria Sharapova swept past Peng Shuai of China 6-2 6-1 and has now spent eight minutes less on court in three matches than Schiavone and Lepchenko did in their single encounter.
Czech fourth seed Petra Kvitova, the Wimbledon champion, had hoped to get a swift win on the Philippe Chatrier court after taking the first set against Nina Bratchikova in 28 minutes. The Russian upped her game however, and Kvitova needed a third set to win 6-2 4-6 6-1 and go through to a meeting with Lepchenko.
Uzbekistan-born Lepchenko was delighted to reach the fourth round of a grand-slam event for the first time. "I was fighting all the way to the end, I was trying to stay with Francesca the whole time," she told a news conference.
"She played amazing and it is her court and I knew that she was not going to give it away for free," added the left-hander, who has risen from 128 at the start of the year to 63 in the rankings. "I had to work really hard, and I did."
Italian Schiavone said she had been happy overall with the way she played but added: "I had my chances, I simply did not take them."