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

Learner Tien, a 19-year-old from California, became the youngest American man to reach the Australian Open's third round since 1990, upsetting No. 5 Daniil Medvedev in five sets.

The 19-year-old American upset fifth-seeded Daniil Medvedev in a five-set Australian Open marathon that lasted nearly five hours.