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

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.

Jannik Sinner kicks off the late session at Rod Laver Arena on a busy day for Italians at the Australian Open on Thursday, while claycourt specialist Iga Swiatek is keeping her expectations low as she bids for a first title on the blue courts of Melbourne.