Learner Tien captured his first career win at a Grand Slam on Thursday, a shock upset over World No. 5 Daniil Medvedev 6-3, 7-6, 6-7, 1-6, 7-6 in the second round of the 2025 Australian Open.
Tien put on an incredible display in Melbourne in a match that lasted four hours and 48 minutes and ended at 2:55 AM local time.
Hailing from Irvine, California, Tien earned a spot in the Open through qualifying and matched up with Medvedev, a three-time Australian Open finalist, following his five-set first-round win over Argentine Camilo Ugo Carabelli.
Tien, 19, becomes the youngest American to defeat a top-five ranked player in a major since 1990.
We covered all you need to know about Tien as he continues his incredible journey at the 2025 Australian Open.
Tien will face Corentin Moutet in the third round of the 2025 Australian Open on Friday, January 17, set to begin at 11:30 PM ET.
The match will take place on Saturday afternoon local time in Melbourne (AEDT).
Tien won three qualifying matches in four days to earn a spot in the men’s singles draw.
Tien defeated France’s Gregoire Barrere, Argentina’s Juan Ficovich, and Slovakia’s Jozef Kovalik in his three qualifying matches.
Read more about how players qualify for tennis Grand Slams here.
Tien’s only Grand Slam appearances have come at the U.S. Open, where he is 0-3.
He had not appeared in any other Grand Slam tournament until the 2025 Australian Open.
Continue reading below for Tien’s Grand Slam history as a junior player.
Tien is ranked No. 121 in the world as of January 13, 2025. His highest ranking was No. 114 in November 2024.
As a junior player, Tien reached No. 4 in the world in both singles and doubles.
Tien has had a very successful junior career, reaching the world No. 4 ranking in both singles and doubles.
He reached the final of both the 2023 Australian Open and 2023 U.S. Open in singles, and won the 2023 Australian Open doubles title.
Tien holds a 76-23 record in junior singles matches.
Tien was born in Irvine, California.
His mother’s profession as a math teacher inspired his first name.
Tien played tennis at the University of Southern California.