Six-time champion Roger Federer was sent crashing out of the Australian Open by 20-year-old Stefanos Tsitsipas on Sunday.
Tsitsipas, who has never previously gone beyond the fourth round at a Grand Slam, came from a set down to beat Federer 6-7, 7-6, 7-5, 7-6 on Rod Laver Arena in Melbourne.
Federer had his opportunities to take charge of the match, failing to convert any of 12 break points as his opponent went through the entire contest without dropping a game on his serve.
It was a superb show of resilience from Tsitsipas, who was on the back foot for much of the pivotal second set but dug in to force a tie-break, which he came through 7-3.
For Federer, who has not lost at the Australian Open since Novak Djokovic ended his 2016 run at the semi-final stage, it ends a bid to win three successive titles in Melbourne.
For the first time all evening, Tsitsipas looked overwhelmed as he stepped out for the on-court interview, saying: "I'm the happiest man on earth right now. I cannot describe it.
"From the very beginning it was very important to keep that mindset, to believe in yourself, believe in your capabilities.
"Roger is a legend of the sport, so much respect for him. He showed such good tennis over the years. I've been idolising him since the age of six. It was a dream come true just being on Rod Laver facing him. Winning at the end, I cannot describe it."
