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.

American qualifier Learner Tien shocked the tennis world on Thursday when he upset last year's Australian Open runner-up Daniil Medvedev in a nearly five-hour, five-set match in the second round. Tien took an early two-set lead (6–3,

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).