Learner Tien, a 19-year-old from California, toppled No. 5 seed Daniil Medvedev at the Australian Open. He’s now the youngest American man to make it this far at a major in nearly two decades.

U.S. 19-year old Learner Tien defeated No. 5 Daniil Medvedev in a fifth set tiebreaker in the Australian Open, making history in Melboune.

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