Defending champion Novak Djokovic, playing his second match in four hours, stormed into the semis of the Toronto Masters on Friday while Canadian Milos Raonic failed to deliver a similar outcome for the home crowd.

Djokovic, who was among several players playing two matches to make up for Thursday's washout, defeated German Tommy Haas 6-3, 3-6, 6-3 hours after dispatching American Sam Querrey 6-4, 6-4 in a contest interrupted by a three-hour rain delay.

The top-seeded Serbian, who needed 2-1/2 hours to get by Haas, will next face fifth-seeded compatriot Janko Tipsarevic, who kicked off the evening session with a 6-4, 6-4 win over Spain's Marcel Granollers.

Tipsarevic had reached the last eight by beating Croatia's Marin Cilic 6-2, 6-4 earlier on Friday.

Raonic, playing in his home tournament for the first time since breaking into the world's top 25, fell 7-6, 6-4 to eighth-seed American John Isner, who earlier edged Germany's Philipp Kohlschreiber.

The big-serving Canadian was on court for the first time since Tuesday, having been handed a walkover to the quarterfinals after Olympic singles champion Andy Murray pulled out due to injury.

While Raonic managed 13 aces in the match, Isner controlled the rallies, clinching the match with a volley to the open court after one of his own booming serves left the 16th seed well out of position.

Isner will now face Frenchman Richard Gasquet, a 5-7, 6-1, 6-1 winner over American Mardy Fish.

Azarenka withdraws

Former Wimbledon champion Petra Kvitova returned to her best on Friday during a Montreal Cup that has been dogged by rain and the withdrawal of world number one Victoria Azarenka.

Kvitova, who also won the WTA Championships last October, is without a title this year but her 6-1, 6-1 thrashing of ninth-seed Marion Bartoli showed she will be difficult to beat.

Aiding the cause of Kvitova, who will play Tamira Paszek in the quarterfinals of the $2 million tournament, was Friday's withdrawal of Azarenka with a knee injury.

Azarenka, who would lose her top ranking should Poland's Agnieszka Radwanska win here, also withdrew from the next week's Cincinnati Open next week but hopes to be fit for the Aug 27-Sept 9 US Open, the year's final major.

Also assisting the Montreal hopes of Kvitova and Radwanska, whose Friday match against Chanelle Scheepers is in doubt due to rain that has again postponed play, is the exit of last year's finalist, Australian Sam Stosur.  US Open champion Stosur lost her third-round clash with 16th seed Lucie Safarova 7-6, 7-6 after wasting several chances.