The Austrian third seed, last year’s losing finalist, appeared to lack energy after rallying to beat Nick Kyrgios over five gruelling sets on Friday in front of a raucous crowd. He struggled to match the intensity of the 18th-seeded Bulgarian on a silent, fan-free Rod Laver Arena and slumped out 4-6, 4-6, 0-6 in two hours and a minute. 

Former world number three Dimitrov will now play giant-killing Russian qualifier Aslan Karatsev in the quarter-finals after the latter stunned 20th seed Felix Auger-Aliassime over five sets. “I feel great. Throughout every season, you have one of those matches where you just keep the ball rolling and it was just one of these days,” Dimitrov said. 

“I was entirely just trying to focus on what I was doing ... I had to very composed against him. Dominic is an extraordinary player.” Dimitrov, who is yet to drop a set, has now reached the quarter-finals or better in Melbourne four times, with his best showing in 2017 when he lost an epic five-set semi-final to Rafael Nadal. 

Thiem looked to be in charge when he raced into a 3-1 lead, but Dimitrov came storming back in an energy-sapping 14-minute game to break back with a backhand passing shot. Later, Novak Djokovic came through a tough examination of his fitness as the top seed beat Canadian powerhouse Milos Raonic 7-6(4), 4-6, 6-1 6-4 to reach the quarter-finals. 

Fourteenth seed Raonic had never taken a set off Djokovic in three previous Grand Slam meetings. So when he snatched the second set, a surprise looked possible. But Djokovic, bidding for a record-extending ninth title in Melbourne, responded by raising his level and improving his record over Raonic to 12-0. 

The Serb will face Germany’s Alexander Zverev for a place in the semi-finals.