Roger Federer's troubled season continued when he followed his crushing loss in the Wimbledon final with a shock defeat by Frenchman Gilles Simon at the Toronto Masters on Wednesday.
Back on court for the first time since his five-set loss to Rafael Nadal at the All-England Club, the world number one appeared ready to take out his disappointment on Simon by winning the first four games on the way to the opening set.
But Simon, riding the momentum from his championship win in Indianapolis on Sunday, refused to buckle under the pressure, battling back to beat the 12-times Grand Slam winner 2-6, 7-5, 6-4 and reach the third round.
It was the first time Federer had lost his opening match in a tournament since falling to Briton Andy Murray in Dubai in March.
"The hard court season just started so it is not the end of the world but I wish I could have started better," Federer told reporters. "I like this surface, I like this tournament, I have done well in the past here so it definitely hurts.
"I have to regroup and look forward. The bigger picture is the Olympic Games and the U.S. Open and those are the places I really want to win so I have to make sure I am ready for that."
The second-round loss at an event he has twice won was another setback for Federer, who was hoping to use the American hardcourt season as preparation for his gold medal bid in Beijing and to re-establish his dominance after a disappointing season.
Federer's number one ranking, which he has held for 234 weeks, is also now under serious threat from his great rival Nadal.
The Swiss held a commanding 1,445-point cushion at the top at the start of the year but if Nadal wins in Toronto for a second time on Sunday the deficit will be sliced to less than 300.
The 22nd-ranked Simon represented a tricky opponent for the rusty Federer, who had only resumed practice four days before arriving in Toronto and received a first-round bye.
Simon, meanwhile, was well into his hardcourt campaign after claiming his fourth career win and second title of the season in Indianapolis with a straight-sets victory over Russian Dmitry Tursunov.
"I was playing like I was in a dream," Simon said. "I just saw the ball and hit it as hard as possible."