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

Defending champion Jannik Sinner's consecutive-sets streak ended in the second round of the Australian Open on Thursday night, but he advanced with a 4-6, 6-4, 6-1, 6-3 victory over wild-card entry Tristan Schoolkate.

Day 5 of the Australian Open was a good day for the higher seeds in the men's and women's draws, with big names advancing to the third round. Men's No. 1 seed Jannik Sinner stumbled early against Australian Tristan Schoolkate by dropping the opening set 4-6.

Jannik Sinner (No. 1 ranking) will take on Marcos Giron (No. 46) in the Round of 32 of the Australian Open on Friday, January 17.Sinner earned a four-set victory over Tristan Schoolkate (4-6, 6-4,

World No 1 Jannik Sinner makes it 16 wins in a row; No 5 seed Daniil Medvedev dumped out of Australian Open by 19-year-old American Learner Tien in five-set epic; Nick Kyrgios and Thanasi Kokkinakis p

The two best men's players in the world are reconfiguring the sport before their opponents' eyes. They don't know what to do about it

Jannik Sinner has started his Australian Open title defense with a challenging win over No. 35-ranked Nicolas Jarry.

Sinner has raced to a 63-18 win-loss record at Grand Slams. On the other hand, his win-loss record at the Australian Open reads as 17-4. Notably, Sinner enjoyed a 23-2 win-loss record at Slams last year.

Sinner became the youngest player to register nine consecutive wins at the Australian Open in the men's singles since Novak Djokovic between 2008 and 2009

Iga Swiatek, a self-described “control freak,” is taking new precautions — including holding on to extra samples of medicine she takes, in case they need to be tested at some point — after a doping case she describes as probably the worst time in her life.