An agitated Alexander Zverev obliterated a racquet as big-serving Milos Raonic ended the German’s Australian Open with an emphatic fourth-round victory.

Raonic, the 16th seed, won 6-1 6-1 7-6 (7-5) against an out-of-sorts Zverev, whose temper flared in another poor campaign at a grand slam.

The 21-year-old fourth seed broke serve in the opening game but from there it was downhill as he surrendered the first two sets in a little over an hour.

Zverev hit three double faults to go down 4-1 in the second set and unleashed his frustration on a racquet, smashing it into the ground nine times.

He stirred late, saving two match points down 5-4 in the third set but Raonic upped his game to close out the tiebreak.

“I played incredible today. I did a lot of things extremely well and I’m very proud of that,” Raonic said.

Zverev beat top guns Roger Federer, Novak Djokovic and Marin Cilic in the London ATP finals to end 2018 but is yet to bring that kind of form to a major.

He has only made the quarter-finals once at a grand slam, the French Open last year.

Raonic, meanwhile, faces either 11th seed Borna Coric or 28th seed Lucas Pouille in the quarter-finals.