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

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 Learner Tien upset No. 5 seeded Daniil Medvedev 6-3, 7-6 (4), 6-7 (8), 1-6, 7-6 (10-7) at the 2025 Australian Open, in a 4-hour, 49-minute match that began Thursday night and ended early Frid