Roger Federer moved a step closer to an elusive French Open title with a 7-6 (7/3), 6-4, 6-4 victory over battling Russian Mikhail Youzhny on Sunday. But it was a far from vintage Federer on display on Court Philippe Chatrier as the world number one continued his campaign to add the Roland Garros crown to his 10-title Grand Slam collection.
The Swiss top seed, who equalled John McEroe's record of 11 successive Grand Slam matches won in straight sets, will now face Spaniard Tommy Robredo, who clinched a 6-2, 7-5, 6-1 win over Italy's Filippo Volandri for a place in the semi-finals.
Victory over Youzhny was Federer's 10th in 10 meetings with the 24-year-old Russian, but he wasn't at his best sending down an uncharacteristic 41 unforced errors.
He also wobbled at the climax of the tie when he needed three match points to secure victory. "It was tough but I stayed calm and I was happy to get through," said the world number one. "Maybe it's because we have similar games. Maybe I hit my forehand better, have more firepower, more confidence.
"I didn't start well today but I got in the groove and I was pretty rock solid." Federer will start as overwhelming favourite to beat ninth seed Robredo, who put out Volandri 6-2, 7-5, 6-1.
He has won all seven times the two have met, including twice on clay, with the Spaniard only managing to take one set off the Swiss and that was five years ago in Vienna. They also met at the same stage at the Australian Open in January where Federer again won in straight sets.
"I have beaten him in clay and in Rome (in 2003) it was pretty easy," said Federer. "I probably have more variety but I've noticed that his game has improved over the last year or so."
The 25-year-old Robredo said he will have to be at the peak of his powers to derail Federer in Tuesday's last eight clash.
"I'm playing the best player in the world so I will have to think about my game plan and my tactics," he said. "I'll have to pull out all the stops and be 100-percent fit to play the match which will be quite physical."
Argentina's Guillermo Canas, the 19th seed, beat compatriot Juan Monaco 6-0, 6-4, 6-2 to reach the quarter-finals for the third time.
Canas, playing his first Grand Slam for two years after serving a 15-month doping ban, will face either Russian fourth seed Nikolay Davydenko or David Nalbandian of Argentina, the 15th seed, for a place in the semi-finals.
If gets through that, Canas could meet Federer who he has already beaten twice this year. Defending champion Rafael Nadal plays his fourth round match against Australia's Lleyton Hewitt on Monday.