The final match of the day saw American Learner Tien, playing in his first major outside of the U.S. Open, upset No. 5 seed Daniil Medvedev in a five-set classic, 6-3, 7-6, 6-7, 1-6, 7-6, that ended at 2:54 a.m. local time. Medvedev had reached three of the past four Australian Open finals, but could not fend off a ferocious Tien.

Defending champ Jannik Sinner drops set for first time since October, but rallies for win; American Danielle Collins plays villain while advancing.

Emma Raducanu, Jannik Sinner, Katie Boulter, Joao Fonseca, Daniil Medvedev, Elena Rybakina and Iga Swiatek all play on Day 5 of the Australian Open - but when a