Rafael Nadal moved to within two matches of a record 21st Grand Slam title with a dogfight five-set quarter-final win over Denis Shapovalov at the Australian Open on Tuesday.

The Spanish sixth seed edged the Canadian 14th seed 6-3, 6-4, 4-6, 3-6, 6-3 in 4hr 8min of thrilling action on Rod Laver Arena to advance to his seventh semi-final in Melbourne where he will face either Matteo Berrettini or Gael Monfils.

It was a gritty win for Nadal over the 22-year-old, who was coming off a straight-sets upset of third seed Alexander Zverev.

"It was very tough today. Honestly I didn’t practise for it," Nadal said.

"Denis was playing great. He is very talented, very aggressive and he was serving huge. It's amazing to be in the semi-finals."

The Spanish legend is tied with great rivals Novak Djokovic and Roger Federer on 20 major titles but with Djokovic forced home by deportation over vaccination issues and Federer injured, the opportunity is there for him to go clear at the top.

Nadal, the 2009 Australian Open champion, had his 2021 season wrecked by a chronic foot injury followed by a bout of Covid-19 in December.

He raced into a two-set lead but was visibly hampered by stomach issues before eventually coming through after a spirited fightback from Shapovalov peppered with winners to all parts of the court.

"I started to feel not well in my stomach. They checked everything was all right with my body," said Nadal, who received medical attention in the fourth set.

"I took some tablets to try and improve my stomach."

Nadal looked on course for a routine straight sets win before Shapovalov hit back to take the quarter-final into a thrilling deciding-set climax.

The Spaniard broke in Shapovalov's opening service game and held on to take the victory.

The feisty Canadian slammed his racquet into the court in anger at losing the epic battle.

There was a testy exchange early in the second set with Shapovalov heard to accuse chair umpire Carlos Bernardes of being "corrupt."

Nadal has a reputation of taking his time between serves right up to the final second of the shot clock and Shapovalov believed the Spaniard deserved a time violation.

"You're looking at the clock so long ago and he's still not ready to play. You've gotta code him," complained Shapovalov.

"He's not ready to play," replied Bernardes.

"Are you kidding me? You are all corrupt," said the Canadian.

Nadal asked Shapovalov what was wrong and the players had a brief discussion at the net to calm the situation.