An ailing Novak Djokovic ground past Grigor Dimitrov on Saturday and into the last 16 as the nine-time Australian Open champion edged closer to a record-equalling 22nd Grand Slam title.
The Serbian fourth seed came through a titanic 77-minute first set before taming the Bulgarian 7-6 (9/7), 6-3, 6-4 on Rod Laver Arena, needing treatment twice on his troublesome hamstring.
He will face home hope Alex de Minaur for a place in the quarter-finals after the 22nd seed equalled his best result at the tournament by breezing past Frenchman Benjamin Bonzi 7-6 (7/0), 6-2, 6-1.
Djokovic's win not only inched him nearer to equalling Rafael Nadal's 22-Slam record but also to a 10th title, which would see him return to world number one for the first time since June.
Victory put him into the last 16 for a 15th time, equalling Nadal in second place on the Open-era list for appearances in the Australian Open fourth round behind Roger Federer's 18.
"Every point, every game mattered," he said. "I think the turning point for both players was right from the blocks, very first game making an early break for me was important.
"Obviously, I didn't know how I'm going to feel physically, it was going up and down.
"It was an incredible battle, three sets over three hours. Let's rest up and prepare for the next one."
Djokovic aggravated his hamstring during his run to a 92nd title at the Adelaide International this month and has been struggling with it since.
He came into the match without his usual off-day practice session to give his leg as much time as possible to recover.
With his left thigh again heavily strapped, the Serb broke immediately and consolidated to take an early grip on the first set.
He was cruising but appeared to feel the injury when moving for a shot at 5-3. He managed to earn three set points, which were saved, but was then broken when serving for the set at 5-4.
Agitated, he complained to the umpire about being given a time violation and was then forced to save two set points before an epic tiebreak.
He eventually got over the line on his fifth set point, having saved another one from the Bulgarian 27th seed, after some intense tennis.
Djokovic took a medical timeout at the changeover and returned to dial up the pressure and take a break before comfortably seeing out the second set.
With Dimitrov flagging, he turned the screws further by breaking twice early in set three and, despite a mid-set wobble when the Bulgarian clawed back and then more treatment on his leg, he battled to the finish line.
De Minaur, who is gunning to make his first quarter-final at Melbourne Park, now awaits after having little trouble getting past Bonzi. The Australian said he was up for the challenge.
"These are the matches you want to be playing," he said. "I'm gonna probably have the best in the world in front of me, and I'm ready for the battle."
© Agence France-Presse