Learner Tien, a 19-year-old qualifier from California, notched the biggest upset of the 2025 Australian Open to date by beating No. 5 seed and 2024 finalist, Daniil Medvedev, in five sets. Tien won 6-3,

American teenager Learner Tien produced arguably the biggest shock of the Australian Open so far as he defeated last year’s runner-up Daniil Medvedev in five sets, 6-3, 7-6 (4), 6-7 (8), 1-6, 7-6 (7).

The Irvine native and 19-year-old qualifier, who played one semester at USC, wins a 4-hour, 49-minute thriller that ends at nearly 3 a.m. in Melbourne

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.

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?

Learner Tien became the first qualifier to claim an ATP top-five win at the Australian Open since Guillermo Garcia Lopez, who defeated Carlos Moya in 2005

At the age of 19, Learner Tien defeated Daniil Medvedev in a five-set thriller that finished just before 3 a.m. in Melbourne.

Inspired American teenager Learner Tien outlasted three-times Australian Open runner-up Daniil Medvedev to reach the third round with a 6-3 7-6(4) 6-7(8) 1-6 7-6(7) victory in a late-night epic on Thursday.