Australian wild-card entry Alexei Popyrin advanced to the third round at Melbourne Park when seventh-seeded Dominic Thiem retired in the third set with an injury.
Popyrin was leading 7-5, 6-4, 2-0 when Thiem retired.
Thiem had a 2 a.m. finish in his first-round match when he beat Benoit Paire in five sets.