Melbourne - Big Canadian Milos Raonic blasted 35 aces to make his fifth Australian Open quarter-final in six years Sunday, outgunning fellow former world number three Marin Cilic in straight sets.
The 32nd seed proved too powerful for the unseeded Croat, winning 6-4, 6-3, 7-5 with Cilic hampered by a back problem after battling through two gruelling five-setters en route to the fourth round.
Raonic's reward is a last-eight clash with either seven-time winner and defending champion Novak Djokovic or feisty Argentinian Diego Schwartzman.
"It was a rollercoaster," said Raonic. "He played better than me in the first set and I was lucky to get through. I'm just happy to be out here, feeling good and playing well."
The Australian Open is Raonic's favourite Slam.
He reached the semi-finals in 2016, when he lost to Andy Murray, and the quarters on three other occasions, including last year.
His career, though, has been plagued by injuries, with operations over the years for hip, foot and wrist problems. He has also struggled with back, ankle, calf and knee issues.
He said it felt "pretty damn good" to finally be injury free.
"I'm happy I have another chance. It's been an exciting tournament for me so far and hopefully there's more exciting times ahead."
Seeded 32, his lowest since 2011, Raonic came into the match after a smooth passage into the last 16 with three straight-sets victories, including a comfortable win over world number six Stefanos Tsitsipas.
In contrast, 2014 US Open champion Cilic was put through two five-setters against seeded opponents, including a gritty defeat of ninth seed Roberto Bautista Agut.
The exertions didn't help Cilic, a 2018 finalist, against a man back to full fitness.
Raonic's power serve is one of the best in the game and he used it to good effect. It was the difference in the opening set, along with his ability to successfully get his racquet on far more returns than the Croat.
While he fired down eight aces, Cilic managed none. The Canadian also successfully sent back 76 percent of the Croat's first serves in contrast to his opponent managing just 44 percent.
The crucial break came in game nine as Cilic lost focus, and Raonic quickly raced to a 3-0 lead in the second set.
Cilic was struggling and took a medical timeout at the changeover for a lower back massage.
He returned to hold serve, but Raonic never allowed him into the match, pumping down another 13 booming aces to go two sets to one in front.
It was more of the same in set three until Cilic worked up two set points at 5-4, but once again Raonic pulled the trigger on some big serves to hold on and then immediately broke before serving out the match, fittingly with another ace.
Collated results on day seven of the Australian Open Grand Slam at Melbourne Park on Sunday (x denotes seeding):
Milos Raonic (CAN x32) bt Marin Cilic (CRO) 6-4, 6-3, 7-5
Novak Djokovic (SRB x2) bt Diego Schwartzman (ARG x14) 6-3, 6-4, 6-4
Tennys Sandgren (USA) bt Fabio Fognini (ITA x12) 7-6 (7/5), 7-5, 6-7 (2/7), 6-4
Roger Federer (SUI x3) bt Marton Fucsovics (HUN) 4-6, 6-1, 6-2, 6-2
Petra Kvitova (CZE x7) bt Maria Sakkari (GRE x22) 6-7 (4/7), 6-3, 6-2
Sofia Kenin (USA x14) bt Coco Gauff (USA) 6-7 (5/7), 6-3, 6-0
Ons Jabeur (TUN) bt Wang Qiang (CHN x27) 7-6 (7/4), 6-1
Ashleigh Barty (AUS x1) bt Alison Riske (USA x18) 6-3, 1-6, 6-4