Learner Tien pulled off a massive upset against Daniil Medvedev at the Australian Open. So, who is Tien, the 19-year-old out of California?

American teen Learner Tien pulled off the biggest upset so far at the 2025 Australian Open, ousting Russian Daniil Medvedev -- the No. 5 player in the world -- in a 4-hour, 49-minute thriller at Margaret Court Arena.

Carlos Alcaraz faces a tricky test in the third round. Novak Djokovic and Aryna Sabalenka will also be in action on Friday in Melbourne.

Learner Tien, 19, became the youngest American man to reach the Australian Open's third round since Pete Sampras in 1990.

Men’s World No. 1 Jannik eyes second successive singles title at Australian Open starting today, while Aryna, leader of the women’s rankings, is gunning for her

Jannik Sinner and Aryna Sabalenka will be the defending champions at the 2025 Australian Open - but who will their biggest rivals be in the singles draws?

Where is Aryna Sabalenka from? Sabalenka ... Along with Sabalenka, several other big names in the tournament such as Daniil Medvedev and Andrey Rublev are also competing under no national flag.

Sinner upset Djokovic in the semifinals here last year before coming back to beat Daniil Medvedev in the final 3-6, 3-6, 6-4, 6-4, 6-3 for his first Grand Slam singles title.

Teenage qualifier Learner Tien stunned last year's Australian Open runner-up Daniil Medvedev after Jannik Sinner roared back to take his place in the third round.

Daniil Medvedev ripped 24 aces and converted six break points to outlast Kasidit Samrej in a 3-hour, 8-minute first-round victory Tuesday at the 2025 Australian Open. No. 9 Andrey Rublev was the latest upset victim.

Defending champions Jannik Sinner and Aryna Sabalenka headlined the men's and women's singles draws, as a star-studded lineup

Sinner upset Djokovic in the semifinals here last year before coming back to beat Daniil Medvedev in the ... defending champions Sinner and Aryna Sabalenka walked into the official ceremony ...