Roger Federer made an imposing start on his hometown stage, with the top seed advancing unhindered into the second round of the Swiss Indoors on Monday when his opponent retired with an ankle injury.
World number two Federer was in total command against 48th-ranked Aleksandr Dolgopolov of the Ukraine leading 6-4 5-2 and serving for the match.
But the youngster's tumble on the hardcourt as he pulled level at 15-15 by unsuccessfully trying for a Federer winner brought about an abrupt end after 48 minutes as Dolgopolov hurt his right ankle.
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A pair of trainers were brought out to the side of the court at the St Jakobshalle, but after a few minutes of grimacing and medical analysis, it looked like season done for the challenger.
Federer quietly accepted the applause from the public at the event where he got his start in the game as a ballboy, happy to leave with nine aces and three breaks of serve.
The three-time champion will await an opponent for the second round as Serb Janko Tipsarevic plays Denis Istromin of Uzbekistan.
Federer has a point to prove his week after Novak Djokovic, this years' second seed, defeated him in the 2009 final to end a run of three consecutive Basel titles.
This year has been less than outstanding for Federer, who lifted his confidence a week ago by winning the Stockholm trophy to go with his Australian Open and Cincinnati honours.
The victory ran his Basel career mark to 34-7 as he starts the bid for his 65th singles title.
American eighth seed John Isner was due for his opener against Frenchman Michael Llodra while Dutch qualifier Robin Haase put out Swiss wild card Stephane Bohli 6-4 6-3 in the week's first match.
