World No.7 Daniil Medvedev was given an early scare before an injury to his opponent gave the Russian a free passage through to the second round of the Adelaide International 1.
Medvedev, the 2021 US Open winner, was leading 7-6 (8-6) 2-1 in Tuesday's match against Lorenzo Sonego when the Italian retired hurt due to an arm injury.
Sonego put up a stern fight in the opening set, saving nine of the 10 break points against him to take it to a tiebreaker.
Medvedev pulled out the goods when it mattered most to clinch the first set, and was handed victory when world No.45 Sonego called it quits early in the second.
"What a match to start the year," Medvedev said during his on-court interview.
"Unfortunate for everybody that it finished early, even if we played one hour 40, but I'm happy to be through.
"I wish Lorenzo a speedy recovery."
Medvedev will take on world No.29 Miomir Kecmanovic in the round of 16.
Australians Thanasi Kokkinakis and Alexei Popyrin are also through to the round of 16 after posting upset wins on Monday.
Kokkinakis beat world No.34 Maxime Cressy 7-6 (7-4) 7-6 (9-7), while Popyrin shocked world No.6 Felix Auger-Aliassime 6-4 7-6 (7-5).
