Marin Cilic shocks Andy Roddick as upsets continue in Toronto

TORONTO (Reuters) - A racket-smashing Andy Roddick was shocked 6-4 4-6 6-4 by 19-year-old Croat Marin Cilic in the third round of the Toronto Masters on Thursday.

With the tennis world still rumbling about world number one Roger Federer's second round upset at the hands of Frenchman Gilles Simon a day earlier, Cilic caused another tremor by disposing the sixth seed in just under two hours.

Simon, coming off what he described as the biggest win of his career, did not suffer any let down as he returned to the court 14 hours later and swept into the quarter-finals with a tidy a 6-3 6-4 decision over Argentine Jose Acasuso.

On a blustery centre court, defending champion Novak Djokovic continued his rock solid play by easing past Swede Robin Soderling 6-4 6-4 to reach the last eight. The 21-year-old Serb remained on course for a semi-final showdown with French Open and Wimbledon champion Rafael Nadal.

"I played as much as I needed, in the important moments I hit some good shots," said Djokovic, winner of three titles this season including the Australian Open.

Roddick, who was contesting only his seventh match since injuring his back at the Rome Masters in early May, appeared baffled by the hard-hitting Cilic.

After dropping the opening set, Roddick broke his 44th-ranked opponent at 5-4 to take the second and even the match but could not carry the momentum into the third as Cilic broke the 2003 Canadian champion to take control.

It would be the only break Cilic would need, holding off an increasingly frustrated Roddick who spent parts of the set arguing with chair umpire and smashing his racket.

"Something doesn't feel comfortable," Roddick told reporters. "It's a little bit across the board.

"My forehand is just not doing anything. I'm missing it and that's the one that I need to click right now."

British eighth seed Andy Murray booked his final eight place with a rollercoaster 6-2 0-6 6-4 win over ninth seeded Swiss Stanislas Wawrinka.

Nadal, who is gunning for his seventh title of season and Federer's number one ranking, takes on Russian Igor Andreev in the evening's showcase match.

(Editing by Pritha Sarkar)