It was an action-packed day, with some of Monday's matches being pushed to Tuesday. Many big names stayed in contention while a former champion saw her run end early. These are the Top 5 photos from Melbourne. (All Photos Getty Images.)
After the grueling ATP Cup, Rafael Nadal is showing no signs of fatigue. The Spaniard rolled to a 6-2, 6-3, 6-0 victory against Hugo Dellien, hitting 38 winners and only making 21 errors in a two-hour match.
Dominic Thiem boosted his head-to-head record to 8-0 after dismissing Adrian Mannarino 6-3, 7-5, 6-2. The Austrian wasn't afraid to step in and control points from the beginning of the match. Thiem will next face Australia's Alex Bolt.
For the fourth consecutive year, Donna Vekic advanced into the Australian Open second round. Vekic defeated former world No. 1 Maria Sharapova, 6-3, 6-4, to continue marching towards the event's second week—which she has yet to appear in.
Madison Keys is moving on after posting a 6-3, 6-1 score over Russia’s Daria Kasatkina. The American reached the Brisbane final before heading to Melbourne, and seems to be bringing the same energy and form to the new week.
Nick Kyrgios put on a show in front of his home crowd in Melbourne. The Aussie eased past Lorenzo Sonego, 6-2, 7-6 (3,) 7-6 (1), to set up a second-round clash with Frenchman Gilles Simon. Kyrgios defeated Simon last season in Washington, D.C.