Dani Medvedev suffered a 6-3 7-6 (7-4) 6-7 (8-10) 1-6 7-6 (10-7) loss to American Learner Tien to crash out of the 2025 Australian Open on Thursday.
Tien, who is ranked 121st in the world, produced an impressive performance to book his place in the third round of the tournament.
It was his first-ever win in a Grand Slam after losing in the first round in all three of his US Open appearances.
Medvedev, who lost in the final to Sinner last year, was a clear favourite to win the game after winning the fourth set in 27 minutes before Tien bounced back to advance in style.
Tien was delighted to qualify for the fourth round of the Australian Open.
He said, “I was hoping it wasn’t going to be a fifth-set breaker but either way, I’m just really happy to get the win.
“I know I made it a lot harder than what it could have been but, you know, whatever.
“Belief is a big thing in succeeding and winning, in general. I always go to the court believing that there’s a chance I can win.
“I wasn’t trying to think of the match as anything more important than any other match I’ve ever played. I was just going to go out there, have fun, and see what I could do.
The 19-year-old won 32 of the 51 points that lasted nine or more strokes, even coming out on top on one that went 45 shots and another that lasted 32.
He became the second-youngest American man to reach the third round at the Australian Open after 18-year-old Pete Sampras in 1990.
