Roger Federer has admitted that he will be tested to the limit when he faces Gilles Simon in the quarter-final of Wimbledon tomorrow.

The number two seed has cruised through to the last eight, losing just one set in his four matches so far and going throughout the tournament without being broken on his serve.

However, Federer - a seven-time champions at SW19 - believes that Simon's returning ability could end that record, and warned that he will not have things all his own way.

"Gilles Simon is one of the best return players we have in the game. I would think I'll be tested a lot. That streak is maybe coming to an end, in my opinion," the number two seed is quoted as saying by PA.

Simon has taken Federer to five sets in both of their previous Grand Slam meetings.