Defending men's singles champion Rafael Nadal and British number one Emma Raducanu both suffered second-round exits on day three of the Australian Open.
Nadal's dreams of a record-extending 23rd Grand Slam title came to an end against the USA's Mackenzie McDonald, losing 4-6 3-6 5-7 in an injury-hit contest.
The men's number one seed was broken in the opening game of both the first and second sets, and he was struggling with a hip issue after falling a set and a break behind.
Nadal managed to carry on into the third set after taking a medical timeout, but he was broken one final time to slump to a shock defeat in four hours and 13 minutes.
Not since losing to Fernando Verdasco in the first round in 2016 has Nadal gone out of the Australian Open so early, and speculation surrounding the Spaniard's possible retirement is heating up again.
Nadal, who was also plagued by an abdominal issues at Wimbledon and the US Open, admitted that the match left him 'mentally destroyed', saying: "I really hope that it doesn't put me out of the court for a long time.
"[I] just can't say that I am not destroyed mentally at this time, because I will be lying. Hopefully, it is nothing too bad. In the end [there] have been three positive weeks in terms of practice."
Former US Open champion Raducanu shared Nadal's fate in the second round, as the 20-year-old lost in straight sets to the USA's Coco Gauff, having also ostensibly suffered from injury.
Raducanu - who overcame a sprained ankle to compete in Melbourne - went down 3-6 6-7 to the 18-year-old in one hour and 42 minutes, although she was seen holding her stomach at several points in the match.
The British number one managed to save two match points in the second-set tie-breaker, but she sent one final tired backhand into the net to render her dogged efforts inconsequential.
Elsewhere on day three, Raducanu's compatriot Cameron Norrie ensured that both British number ones would not suffer second-round exits, as he recovered from a second-set blip to defeat France's Constant Lestienne.
In a thrilling contest that ended just before 1.30am local time, Norrie - who hit a whopping 16 aces on the night - came through 6-3 3-6 7-6 6-3 in three hours and 13 minutes.
Norrie has been rewarded with a third-round tie against Jiri Lehecka, and he has been joined in round three by Jannik Sinner, Daniil Medvedev, Frances Tiafoe, Stefanos Tsitsipas and Felix Auger-Aliassime, the latter of whom came from two sets down to defeat Alex Molcan 3-6 3-6 6-3 6-2 6-2.
Women's number one seed Iga Swiatek cruised past Camila Osorio 6-3 6-2 to advance to round three, while Madison Keys, Jessica Pegula and Maria Sakkari also made it through, although the latter had to come from a set behind to defeat Russian 18-year-old Diana Shnaider.
Wimbledon champion Elena Rybakina also progressed, but eighth seed Daria Kasatkina and 14th seed Beatriz Haddad Maia were knocked out in the first round by Varvara Gracheva and Nuria Parrizas-Diaz respectively, having resumed their opening matches on Wednesday due to previous adverse weather.