Learner Tien, 19, became the youngest American man to reach the Australian Open's third round since Pete Sampras in 1990.
Learner Tien Beats Daniil Medvedev and Is the Youngest US Man in Australia's 3rd Round Since Sampras MELBOURNE ... shortly before 2:30 a.m. with Tien serving at 5-all, 15-all in the fifth set.