Learner Tien won again at the Australian Open today, knocking out France’s Corentin Moutet to progress to the fourth round of the men’s singles.

Two friends from California, Learner Tien and Alex Michelsen, have both reached the fourth round at the Australian Open. Tien is 19, and Michelsen is 20.

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,

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, a 19-year-old qualifier from California, became the youngest American man to reach the Australian Open's third round since Pete Sampras in 1990, upsetting a racket-tossing Daniil Medvedev 6-3,

Two of four American men still playing in Melbourne, Irvine native Tien, 19, and Aliso Viejo native Michelsen, 20, became friends on the youth tennis circuit