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).

Learner Tien, a 19-year-old qualifier from California, notched the biggest upset of the 2025 Australian Open to date by beating 2024 finalist and No. 5 seed, Daniil Medvedev in five sets, 6-3, 7-6(4),

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

The 19-year-old who was a late qualifier to the Grand Slam secured the biggest win of his young career on Thursday

Learner Tien has become the youngest American man to reach the Australian Open’s third round since Pete Sampras in 1990

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 Daniil Medvedev in five sets on Thursday.