Rafa Nadal's Australian Open title defence lay in ruins on Wednesday after an injury-plagued defeat that shook up the men's draw, even as rain wreaked further scheduling havoc at Melbourne Park on day three.
A wincing Nadal suffered a left hip problem midway through his 6-4 6-4 7-5 loss to American Mackenzie McDonald at Rod Laver Arena and gloomily played out the match in pain.
The result not only opens up the top half of the draw, it also hands Novak Djokovic a boost as the Serb hunts a 10th title at Melbourne Park to draw level with Nadal's 22 major triumphs in the Grand Slam race.
"It has been like this a couple of days," said Nadal of his injury.
"I have a history of hip issues.
"I've had to do treatments in the past but it was not this amount of a problem."
For all Nadal's struggles, hard-hitting McDonald was hugely impressive and had the better of the match before his veteran opponent broke down.
Humiliated by Nadal at the same stage of the 2020 French Open, their only previous meeting, McDonald was glad to square the ledger.
"Last time I played him was at Chatrier, he kicked my butt," said world number 65 McDonald.
"He's an incredible champion, he's never going to give up regardless of the situation so even closing it out against a top guy like that is always tough."
Another shock appeared set to rock Melbourne Park when Felix Auger-Aliassime went two sets down against Alex Molcan at Margaret Court Arena but the Canadian sixth seed rallied to close out the match 3-6 3-6 6-3 6-2 6-2.
Under the roof
There was less tension in the women's side, as Iga Swiatek, hot favourite for the women's title, overcame Camila Osorio 6-2 6-3 under the roof on Rod Laver Arena.
A highly-anticipated first meeting between tennis prodigies went the way of Coco Gauff, who outshone Briton Emma Raducanu to win 6-3 7-6(4) in the evening session – offering fans a glimpse of the future of women's tennis in the post-Serena Williams era.
Daniil Medvedev stayed on course to reach a third successive final at Melbourne Park with another straight-sets victory, as the Russian flexed his muscles to ease past Australian John Millman 7-5 6-2 6-2.
Stefanos Tsitsipas was equally dominant against another home hope in Rinky Hijikata as the Greek third seed won 6-3 6-0 6-2.
Men's dark horse Jannik Sinner, who has reached the quarter-finals of all four Grand Slams but never gone any further, also swept into the third round by waltzing past Tomas Etcheverry 6-3 6-2 6-2 on the similarly protected John Cain Arena.
Rain kept the players off the outer courts throughout the day session, however, adding to fixture congestion triggered by extreme heat and storms on Tuesday when nine matches did not get started and two could not be completed.
Matches eventually got going following a delay of over six hours and after waiting nearly a day, Thanasi Kokkinakis needed three minutes and five points to dispatch Fabio Fognini 6-1 6-2 6-2 and set up a second-round match with Andy Murray.
It was a good day for the Americans – winners of the United Cup team event – as Jessica Pegula downed Aliaksandra Sasnovich 6-2 7-6(5) while Madison Keys and Frances Tiafoe beat China's Wang Xinyu and Shang Juncheng to stay "locked in".
"I made a joke about it with the guys... asking them before the match, 'are you locked?'," Tiafoe said. "I've been kind of living by that for a little bit.
"You've seen the shift in myself in being just locked in everything you're doing, staying super present, staying in the moment, staying locked in."
Greek sixth seed Maria Sakkari had a scare on Margaret Court Arena against 18-year-old Diana Shnaider and was forced to come from a set down to beat the Russian teenager 3-6 7-5 6-3 over more than 2-1/2 hours.
"It was a high level from both of us, she played an amazing match, she's talented, promising," said Sakkari, before joking that Shnaider should consider giving up her college eligibility in the US and turn professional.
Bianca Andreescu crashed to a 2-6 7-6(7) 6-4 defeat by Cristina Bucsa while Petra Kvitova fell 7-5 6-4 against Anhelina Kalinina and Sloane Stephens was beaten 7-6(2) 6-4 by Anastasia Potapova as Grand Slam champions continued to tumble out.
But Wimbledon champion Elena Rybakina returned to the spotlight of John Cain Arena after her Court 13 opener to dispatch Kaja Juvan 6-2 6-1, while 2021 French Open winner Barbora Krejcikova beat Clara Burel 6-4 6-1.
Victoria Azarenka, Australian Open champion in 2012 and 2013, lost only one game en route to beating Nadia Podoroska.