Canada's Denis Shapovalov launched a stunning tirade at the chair umpire during his Australian Open quarterfinal defeat to Rafael Nadal

Canadian star Denis Shapovalov branded the umpire "corrupt" as the youngster launched an astonishing tirade after being angered by rival Rafael Nadal's slow play during their Australian Open quarterfinal.

Aiming to capitalize on the absence of Novak Djokovic in his quest for a record 21st Grand Slam title, Nadal won an epic five-set tussle with Shapovalov in the Melbourne heat.

Nadal raced into a two-set lead before being pegged back by the 22-year-old, but despite requiring medical treatment for an apparent stomach issue, the veteran Spaniard scrapped to win the decisive set and take the match 6-3 6-4 4-6 3-6 6-3 - booking himself a semifinal spot as he aims to win what would be a second Melbourne title.

But Tuesday's meeting at Rod Laver Arena was not without controversy, as Shapovalov launched an extraordinary outburst as he lined up to serve to begin the second set when Nadal appeared unready.

The Canadian 14th seed was furious that the serve clock was running yet he couldn't begin because of Nadal.

"Started the clock so long ago and he's still not ready to play. You've got to code him," Shapovalov raged at umpire Carlos Bernardes as he demanded a violation for Nadal.

After Bernardes replied that Shapovalov wasn't ready either because he was too busy remonstrating, the youngster fired back: "Are you kidding me? You guys are all corrupt."

The tension wasn't done there as Shapovalov vented his frustration not long afterwards, apparently in protest at Nadal taking his time to get going on his serve.

"You have eight seconds [left] to play, what do you want? Why are you looking at me like I need to watch, you have the shot clock for this," Bernardes pointed out.

Nadal - who has faced fury from opponents in the past because of his labored approach to serving - then moved towards the net to speak with the hot-headed Canadian, in an apparent effort to defuse the situation.

The Spaniard wrapped up the second set and appeared to be cruising towards the semifinals before Shapovalov launched a comeback, winning the third set 6-4.

Nadal called for medical assistance during the fourth set as he trailed 1-4, receiving treatment for what seemed to be a stomach issue in the stifling Melbourne heat.

Shapovalov took the set 6-3 to send the match to a decider, with Nadal taking time off court for a medical examination before the start of the fifth set.

But just when the 35-year-old seemed on the ropes, he broke Shapovalov in the second game of the decider as the Spaniard reeled off three games in a row to put him back in the driving seat.

Nadal didn't look back, seeing out the set 6-3 on his serve.

There was one final outburst from Shapovalov as he obliterated his racket before moving to congratulate Nadal at the net.

Having entered this year's Australian Open with lingering concerns over his fitness and his preparations disrupted by a Covid infection, Nadal is now just two wins away from a 21st Grand Slam title - which would move him one ahead of absent rivals Djokovic and Roger Federer in the all-time rankings.

Seeded sixth, Nadal will play either Gael Monfils of France or Matteo Berrettini of Italy in the semifinal at Melbourne Park.

(RT.com)