WATCH: Federer comes up with clutch shot in Swiss Indoors quarterfinal

Roger Federer says he surprised himself with his backhand winner down break point against Adrian Mannarino in the quarterfinals of Basel.

Federer was serving at 2-3, 30-40, in the third set when Mannarino drilled the ball deep toward the baseline. But Federer, standing there, produced a stunning winner off a backhand half-volley. Mannarino did not win another game as the top seed took command of the meeting from that point.

"When I won this point, I thought Mannarino could take a bit of a psychological hit," Federer told local press. "If I play this point 100 times, I think I win it like five times. I made a good choice ... left myself room to play the half-volley. But I would never anticipate it would finally transform into a winner down the line."

Federer, despite producing a high amount of unforced errors, hit several backhand winners during the match, including on match point.

Federer is a seven-time champion at Basel.