Stefanos Tsitsipas beat Spain's Roberto Bautista Agut in four sets to continue his superb run in Melbourne and reach the Australian Open semi-finals.
At 20 years and 168 days, Tsitsipas is the youngest man to reach the last four of a Grand Slam since Novak Djokovic at the 2007 US Open.
The Greek 14th seed won 7-5 4-6 6-4 7-6 (7-2) in three hours and 15 minutes.
He will face Spanish 2009 champion Rafael Nadal or unseeded American Frances Tiafoe next.
"It all feels like a fairytale almost. I'm just living the dream, living what I've been working for," he said.
"I feel a bit emotional but not too much because I know I really worked hard to get here."
Tsitsipas became the first Greek player to go beyond the fourth round of a Grand Slam when he knocked out six-time champion Roger Federer to reach the quarter-finals.
He is the youngest man to reach the last four in Melbourne since Andy Roddick in 2003.