Roger Federer was the two-time defending champion, but lost in the fourth round to Stefanos Tsitsipas. Tsitsipas became the first Greek player to reach the semifinals at a singles major,[2] after becoming the first man representing Greece to win a main-draw singles match at the Australian Open.[3]
This was the first Australian Open since 1982 to feature a final set tie-break.[citation needed] Upon reaching 6–6 in the fifth set, a match tie-break is played where the winner is the first to reach ten points and lead by two points.[4] The first men's singles main-draw match to feature the ten-point tiebreak was the first-round match between Jérémy Chardy and Ugo Humbert.