Rafael Nadal of Spain hits a return against Mischa Zverev of Germany in their men's singless second round match at the Brisbane International tennis tournament in Brisbane on January 5, 2017. [Photo/VCG]

Former world number one Rafa Nadal bulldozed Mischa Zverev 6-1 6-1 in the Brisbane International on Thursday to set up a mouth-watering quarter-final clash with defending champion and top seed Milos Raonic.

The 14-time grand slam champion, seeded fifth on his return from a wrist injury that forced him to end his 2016 season in October, took 55 minutes to sweep aside his German opponent in a one-sided contest between two left-handers.

"It's going to be a tough match," Nadal said of his match against Raonic. "His serve is huge so I will need to return aggressively."

Raonic began his title defense with a 6-3, 6-2 win against Argentine Diego Schwartzman.

Better known for his groundstrokes, the Canadian came to the net 22 times, suggesting serve-volley specialist and former Wimbledon champion Richard Krajicek - who Raonic added to his coaching team last month - is already exerting an influence.

But he lost 10 of those points, a rate of return he will want to improve on.

"I probably should have approached (the net) 12 more times and I probably should have won a few more," said the world number three.

"...I hesitated, but also, with him, you've got to understand that he's quite quick. So rarely do you get him sort of reaching for balls," added Raonic, who smashed 12 aces and won 75 per cent of his first-service points.

Former finalist Grigor Dimitrov beat French veteran Nicolas Mahut 6-2 6-4 to set up a quarter-final clash with Austria's Dominic Thiem who beat Australian wildcard Sam Groth 7-6(5), 6-3.