Canadian Milos Raonic defeated Spain's Tommy Robredo 6-4, 6-3 on Thursday to reach the quarter-finals at the Monte Carlo Masters.

The 23-year-old from Thornhill, Ont., will next take on Australian Open champion Stanislas Wawrinka, who advanced on a walkover when Spanish opponent Nicolas Almagro retired before their match with a foot injury.

Wawrinka, the third seed, has beaten the eighth-seeded Raonic in both of their previous meetings.

"I've struggled in the past against Stan but it will be quite different this time around," said Raonic. "I'm doing a lot of things well and I'm looking forward to that challenge."

Raonic had seven aces in his third-round match and broke Robredo's serve once per set while never facing a challenge on his own serve. The Canadian also beat Robredo in their previous meeting last spring in Barcelona.

His next match marks a breakthrough as it will be Raonic's first quarter-final appearance at a clay-court 1000 Series event.

"This is a first, that's for sure," he said. "It's a result of a lot of the good things I'm doing. But I can do better and I'm looking forward to bringing that out in myself.

"This is the closest I've gotten to a big clay opportunity, so it's definitely a positive."

In second-round men's doubles play, Toronto's Daniel Nestor and Serbian partner Nenad Zimonjic defeated the Polish duo of Mariusz Fyrstenberg and Marcin Matowski 6-7(6), 7-6 (3), 10-7.

'I'm very pleased with myself, I showed a lot of discipline. I struggled in the beginning but was able to figure it all out towards the end of the set.'- Canadian tennis star Milos Raonic

Raonic claimed the opening set against Robredo with a break in the final game, smashing down an overhead winner on his second set-point opportunity.

Early lead

The Canadian jumped out to a 2-0 lead in the second set when a Robredo return wide down the line. Raonic then stayed the course to serve out the victory, finishing in just over an hour.

"I'm very pleased with myself, I showed a lot of discipline," Raonic said. "I struggled in the beginning but was able to figure it all out towards the end of the set. I gave myself a lot of opportunities afterwards."

As usual, Raonic credited his world-class serve with keeping him out of trouble.

"Serving well was a big thing today," he said. "I was also moving well and able to dictate with my forehand."

The victory boosted Raonic's record to 10-3 on the season and has given him a boost of confidence on the slower surface.

"I've played a lot of the Spanish guys in practice matches," said Raonic, the former pupil of Spaniard Galo Blanco. "I definitely have more of an understanding of what I need to do and what I can expect from them as well."

Also Thursday, defending champion Novak Djokovic of Serbia raced into the quarter-finals by dispatching Pablo Carreno Busta 6-0, 6-1 in just 47 minutes.

Eight-time champion Rafael Nadal also had little trouble reaching the last eight, beating Italian Andreas Seppi 6-1, 6-3, while fourth-seeded Roger Federer shook off a slow start in a 6-4, 6-1 win against Czech player Lukas Rosol.

The second-seeded Djokovic had won his second-round match in 45 minutes and has not been tested this week, while the top-seeded Nadal has looked a bit sloppy at times.

Djokovic took only 22 minutes to win the first set, sealing it with a crisp forehand that glided past Carreno Busta. His Spanish opponent then received loud cheers, clenched his fists and grinned broadly when he won his first game to pull back to 3-1 in the second. Djokovic served out the match, tormenting him one last time with an exquisite drop shot.

Clinical

Having looked a little rusty in the second round on Wednesday, where he trailed 3-1 against Teymuraz Gabashvili, the Spaniard was more clinical this time and raced to a 4-0 lead.

"I think today I played a little bit better than yesterday," said Nadal, who lost last year's final to Djokovic. "I was playing at a good level, changing the directions very well, playing with the right intensity."

He next faces sixth-seeded David Ferrer, who easily beat No. 12 Grigor Dimitrov 6-4, 6-2, while Federer will face ninth-seeded Jo-Wilfried Tsonga, and Djokovic takes on either No. 5 Tomas Berdych or Guillermo Garcia-Lopez.

Nadal has a 21-5 career record against Ferrer, winning 10 of the past 11 meetings since Ferrer beat him in straight sets at the Australian Open in 2011 — the year he also lost to Nadal in the Monte Carlo final.

The top-seeded Nadal was only briefly troubled in the second set when Seppi broke him at love to pull back to 4-3 down. But Seppi could not hold and Nadal completed the victory with an ace on his first match point.

Nadal won the tournament eight times in succession before losing last year's final to Novak Djokovic.

He was a little sloppy in the sixth game of the first set and had to save five break points, but dominated most of the match from the back of the court and sometimes used his drop shot to good effect to move the taller Seppi around.

Federer has a 10-4 record against Tsonga, who beat him in the French Open quarter-finals last year and in the Wimbledon quarters in 2011.

"I've seen Jo play different kind of quality matches lately, so not quite sure he's going to play, how aggressive, how passive," Federer said. "I'm going to have to have an open mind."

Tsonga won 5-7, 6-3, 6-0 against 10th-seeded Fabio Fognini of Italy, who did his best to spoil the Frenchman's 29th birthday with his wild antics, including smashing rackets and shouting loudly.

With files from The Associated Press