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.

Jannik Sinner has announced that he will part ways with his coach Darren Cahill at the end of the season. The Australian, who joined Sinner's team in July 2022, will conclude the 2025 campaign before stepping back from full-time tennis.

Danielle Collins got the last laugh — and a "big fat paycheck" — at the 2025 Australian Open. Fans didn't hold back on Collins, 31, when she defeated Australia's Destanee Aiava on Thursday, Jan. 16.

Danielle Collins has gotten into a back-and-forth with a booing crowd at the Australian Open after eliminating a local player

Danielle Collins played up a hostile crowd during her second-round win at the Australian Open against home favorite Destanee Aiava.