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.

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).

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