Federer, Nadal crash out of Montreal Masters

Roger Federer suffered a stunning collapse and Rafael Nadal's creaky knees weren't strong enough to carry him into the semi-finals as the world's top two players crashed out of the Montreal Masters.

With the world's eight top-ranked players featuring in the quarter-finals of an ATP Tour event for the first time since official rankings began in 1973, ticket-holders looked forward to a spectacular day of tennis at Stade Uniprix and were not disappointed.

Frenchman Jo-Wilfried Tsonga's dramatic 7-6 1-6 7-6 comeback win over Swiss world number one Federer set the pace before towering Argentine Juan Martin Del Potro ended Nadal's Montreal title defence with a clinical 7-6 6-1 win.

Apart from losing the match and the championship, the Spaniard may yet lose his world number two ranking to Andy Murray, who cruised to a 6-2 6-4 quarter-final victory over Nikolay Davydenko.

With Federer playing his first tournament since lifting a record 15th grand slam title at Wimbledon, and Nadal back in action after being sidelined for more than two months with knee tendonitis, there was already little hope the two could renew their great rivalry on the Canadian hardcourts.

Seventh-ranked Tsonga ended any chance of a dream final early in the day, coming back from 5-1 down in the third set to hand the Swiss one of his most stunning defeats.

After winning five consecutive games to force the set to a tie-break, the big-hitting Frenchman triumphed 7-3 in the decider to snap a 21-match winning streak for Federer and leave the capacity centre court crowd stunned.

"It happens in tennis, it's never over until it's over and it showed today," Federer told reporters.

"I think I should have won the first and he completely lost his game for an hour there.

"That's what Jo does. He doesn't make a return for three hours, then he puts in a few and then all of a sudden he's back in the match.

"I never should have allowed it but it happened."