Rafael Nadal has defended world No.1 Novak Djokovic, claiming he didn’t deserve to be booed after retiring hurt against Stan Wawrinka at the US Open.

The Spaniard had the crowd at Arthur Ashe Stadium - including Tiger Woods - roaring with delight after a plethora of incredible shots against Marin Cilic.

‘ABSOLUTELY INSANE’: Nadal stuns US Open with ‘unbelievable’ act

The energy in the stadium was electric and Nadal received the full support of the fans as he overcame a tough second set to advance in four to set up a showdown with Diego Schwartzman in the quarter-final.

But after the match, Nadal was questioned whether his long-time rival, Djokovic, deserved the ire of the crowd after the Serb retired due to his left shoulder against the

hard-hitting Wawrinka.

The incident was labelled “absolutely shameful” and “disgusting”, despite Djokovic showing his class and thanking the crowd despite the animosity.

While the Spaniard was not aware this had happened, he said Djokovic “doesn’t deserve” to be booed for being injured.

“No, I really believe that he doesn’t deserve [to be booed] of course,” Nadal said.

"I believe that he's a super athlete.

“If he had to go, [it] is because he was not able to continue at all.

“For him, [it] is much more painful than for anyone at that Arthur Ashe Stadium.

“He missed an opportunity to win another grand slam.”

Nadal pulls off incredible winner

Nadal left the tennis world in shock with an insane winner in his victory over Cilic.

In the final game of his 6-3 3-6 6-1 6-2 fourth-round victory on Monday, Nadal produced a spectacular around-the-net winner that he had absolutely no right to pull off.

‘WHAT IN THE WORLD’: Nadal goes missing in bizarre disappearing act

Cilic appeared to have sewn up the point with a precise backhand volley, but Nadal somehow tracked it down before hitting a forehand around the net and landing it in.

Fans leapt to their feet in a standing ovation that actually delayed the next point.