American teenager Learner Tien on Saturday became the youngest male player to reach the fourth round of the Australian Open since Rafael Nadal in 2005. The 19-year-old southpaw beat unseeded Frenchman Corentin Moutet in straight sets, 7-6, 6-3, 6-3, in the third round to set up a fourth-round clash with Italian veteran Lorenzo Sonego.

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

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).

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.

By Ian Ransom MELBOURNE (Reuters) -Teenage qualifier Learner Tien became the youngest man to reach the Australian Open fourth round in 20 years as the future of American tennis lit up Melbourne Park on Saturday.