Roger Federer battled through to the Toronto Masters semi-finals with a 7-6, 6-7, 6-3 win over Xavier Malisse on Friday.
Playing his first event since claiming his fourth consecutive Wimbledon title, the world number one has yet to slip into a comfortable rhythm and for the second consecutive night was taken to three sets.
Although Federer needed two hours and 30 minutes to put away Malisse, however, the Belgian seldom looked capable of halting the Swiss player's 51-match winning streak on north American hard courts.
Federer, who celebrated his 25th birthday on Tuesday, has not lost a hardcourt match in north America since falling to Dominik Hrbaty in the first round of Cincinnati Masters in August 2004.
"First set when he was breakpoint up at 5-5, I thought this could be a tough match," Federer told reporters. "But I ended up winning the tiebreaker and after that it was never really in doubt too much.
"It just felt like it was tough out there tonight. For some reason I didn't feel that comfortable."
Chile's Fernando Gonzalez and Argentine Jose Acasuso meet in an all-South American quarter-final later on Friday with the winner earning the next chance to stop Federer reaching his 17th consecutive final.
The other semi-final brings together two of the game's emerging talents, Briton Andy Murray and Frenchman Richard Gasquet.
With an early break to go up 4-1, Federer looked poised for a comfortable win but Malisse dug in and broke back, sending the set into a tiebreak that the Wimbledon champion won 7-4.
EARLY BREAK
Federer again seized the initiative in the second set with an early break but Malisse continued to battle, forcing another tiebreak which he won 7-5 to force a decider.
The effort, however, appeared to take its toll on the Belgian and Federer stepped up the pressure, sweeping through the third set without allowing Malisse a break point.
"Today was the first time I played him in four years since he's been playing on a different planet," said Malisse. "It's possible to beat him but you have to be 100 percent the full match.
"You can't slack one game or he's on top of you. I think that's what makes him so great.
"In one way you feel disappointed because you played a good match and you get so close to winning. You don't get that chance very often."
Riding the momentum of his appearance in the Washington final last week, Murray battled into the last four at a Masters Series for the first time with a testing 6-4 6-7 6-3 win over Finland's 14th seed Jarkko Nieminen.
Gasquet booked his place with a 6-4 6-1 win over 13th-seeded Czech Tomas Berdych, who upset defending champion Rafael Nadal in the third round.
After a slow start to the season the 20-year-old Gasquet has been in sizzling form since the French Open, capturing two titles and compiling a 15-3 record with two of those defeats inflicted by Federer.
The 19-year-old Murray, who confirmed a changing of the guard in British tennis with a second-round win over Tim Henman, has also been in superb form, posting a 17-4 record since mid-June.