Novak Djokovic has been forced to come from two sets down against Italian teenager Lorenzo Musetti to reach the French Open quarter-finals, with Musetti retiring hurt in devastating scenes late in the fifth set.
Djokovic was completely outplayed by Musetti as he lost the first two sets in tie-breakers, but the match changed dramatically as the Serb fought back to win 6-7(7) 6-7(2) 6-1 6-0 4-0 and reach the last eight in Paris for the 15th time.
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The World No.1 will now play another Italian after Matteo Berrettini was handed a walkover after Roger Federer's withdrawal.
It was unclear exactly what happened to World No.76 Musetti, whose stylish game was threatening to send Djokovic to his earliest Roland Garros exit since 2009.
Having produced tennis of the highest calibre in two sensational sets, Musetti then lost the third set in 24 minutes and did not even get a point in set four until the fifth game as the match slipped away from him.
A relieved Djokovic went 4-0 ahead in the decider before Musetti quit, in an anti-climactic end to what was brewing up to be a seismic shock in a tournament already full of surprises.
Djokovic said he had felt nervous before the match and even "liked" the fact he lost the opening two sets.
"I don't know, I just played under certain kind of tension and wasn't able to go through my shots," he told reporters.
"Just not playing and not feeling great in the first couple of sets. But credit to him for playing well in important moments.
"After I lost the second set and went out to change and came back, I just felt different. I was a different player."
Fans were left in disbelief as the match was completely flipped on its head, with many expressing their sorrow for Musetti.
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Djokvovic dismissed concerns over his fitness heading into the quarter-finals.
"I like to play young guys in the best of five because even at two sets down, I feel I still have my chances," said the 18-time major winner.
"I feel physically fit, I have won most of my five-setters and that experience helps."
It was the fifth time in his grand slam career that 34-year-old Djokovic has come back from to sets down.
Djokovic, the 2016 champion and chasing a 19th major, reeled off 53 of the last 61 points as he made a quarter-final at the majors for the 49th time.
"I was not able anymore to win a point, and so I decided to retire," said Musetti.
"But it was a fantastic experience for me. I was playing my best tennis."
Meanwhile, third seed Rafael Nadal downed 18th-seeded Jannik Sinner 7-5, 6-3, 6-0 and goes on to face Diego Schwartzman - who he defeated in the semi-finals in 2020.
Nadal has now won 104 matches at Roland Garros against just two defeats since his 2005 debut, while Monday's victory extended his run of consecutive sets won in Paris to 35.
The 35-year-old Spanish World No.3 is projected to face Djokovic in the semi-finals.
"I started well but was a little too defensive," said Nadal after reaching a 44th slam last-eight.
"I gave him the chance to come inside the court and play his best shots. That was a mistake.
"I broke back at 5-4 in the first set and the match changed after that. I played at a great level."
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