Nick Kyrgios has charged home from two sets to one down to defeat 29th seed Ugo Humbert.
Kyrgios saved three match points after falling two sets to one down before powering back into the match to win 5-7, 6-4, 3-6, 7-6, 6-4.
Earlier in the night, Ajla Tomljanovic missed a golden opportunity to defeat the world number two Simona Halep.
Leading 4-6, 6-4, and serving at 5-3 in the deciding set Tomljanovic lost four games in a row to concede defeat 5-7.
Meanwhile, Bernard Tomic was knocked out in straight sets to Canadas Denis Shapovalov 1-6, 3-6, 6-2.
James Duckworth also lost in straight sets.
Ash Barty and Daria Gavrilova will play an all Aussie affair on Wednesday in second round women's single action on Rod Laver Arena.
Alex Di Minaur, Thansi Kokkanakis, Chris O'Connell and Alex Popyrin all all feature in men's second round action.