Rafael Nadal's Australian Open title defence has come to a dramatic end with the legendary Spaniard hit by injury during a shock second-round loss at Melbourne Park.
Nadal grabbed at his left hip during the eighth game of the second set of his clash with American Mackenzie McDonald, immediately going off court for medical attention.
The 36-year-old resumed playing on Rod Laver Arena but was clearly in pain and struggling to run as world No.65 McDonald closed out the biggest win of his career 6-4 6-4 7-5.
Nadal's box, including wife Maria who wiped away tears, was left shattered by the injury as the 22-time major winner seemingly approaches the end of his glittering career.
After the loss, Nadal slowly walked off court and made extra time to acknowledge the crowd in what could be his final appearance at Melbourne Park.
Alexander Zverev recently predicted Nadal would retire after this year's French Open but the German's call was quickly brushed off by the 14-time winner at Roland Garros.
Despite winning two majors last year, Nadal entered this tournament out-of-form, and has now lost seven of his last nine singles matches.
Even before the injury, Nadal was rattled by McDonald, who broke serve in the opening game of the match.
Nadal became frustrated, arguing multiple times with the chair umpire.
The apparent hip problem marks the sixth time in his grand career that either injury or illness has cruelled his Australian Open campaign.
He retired in the 2010 quarter-finals against Andy Murray with a knee injury and was badly hindered by a hamstring strain the following year in a last-eighth loss to countryman David Ferrer.
Nadal withdrew from the Open in 2013 with a stomach virus and suffered a back injury in the warm-up before losing the 2014 final to Stan Wawrinka.
In 2018, the great Spaniard quit his quarter-final against Marin Cilic with a hip issue.
Nadal last year finally won a second Australian Open title, 13 years after his first, by coming from two sets down to defeat Russian Daniil Medvedev in a classic decider.
The world No.2's early exit is another blow for Australian Open organisers, with the draw already ravaged by major withdrawals and retirements.
Women's titleholder Ash Barty, seven-times champion Serena Williams, her sister Venus, dual winner Naomi Osaka, world No.1 Carlos Alcaraz and the legendary Roger Federer are all missing.
Tennis Australia boss Craig Tiley was captured with a grim look on his face during Nadal's medical timeout.
McDonald praised Nadal's resilience, admitting he was thrown out of "rhythm" by the gritty left-hander playing differently due to the injury.
"He's an incredible champion," the 27-year-old said.
"He is never going to give up regardless of the situation.
"Even closing it out against a top guy like that is always tough.
"I was trying to stay so focused on what I was doing."