Novak Djokovic says he 'probably wouldn't be playing' if he was not in the middle of a Grand Slam campaign.
The top seed made his way through to the quarter-finals with a 3-1 win over Milos Raonic on Sunday morning.
However, he has been battling a stomach injury which threatened his involvement in the tournament.
"It's not ideal, I've felt better," he said after his win, when asked about his condition.
"I didn't have much of a preparation for this match, I didn't hit a tennis ball since two nights ago."
Having won the opening set, Djokovic lost the second set but responded in positive fashion to take the third and fourth.
The highly-rated Raonic, who was the competition's 14th seed, was unable to stop the Serb despite clinching the second set.
— #AusOpen (@AustralianOpen) February 14, 2021
Djokovic is chasing an 18th Grand Slam title, and a ninth Australian crown.
He will, however, have to manage his injury.
Commenting on his preparation, Djokovic said:
"I warmed up a couple of hours before tonight's match to really see how I would feel. If I wasn't in the condition, I would pull out.
"There was a big cloud of doubt whether I'm going to play or not but it's a grand slam and, for me, at this stage of my career, this means everything.
"If it was any other tournament, I probably wouldn't be playing.
"I just want to try to feel better and better as this tournament progresses. Because I'm under painkillers, very strong ones, for 48 hours, I don't know exactly the damage that has been done."
He progresses to meet Alexander Zverev in the last eight.
Qualifier Aslan Karatsev is on the same side of the draw.
He plays 18th seed, Grigor Dimitrov, in the last eight clash with the winner set to meet either Djokovic or Zverev.