Daniil Medvedev ripped 24 aces and converted six break points to outlast Kasidit Samrej in a 3-hour, 8-minute first-round victory Tuesday at the 2025 Australian Open. No. 9 Andrey Rublev was the latest upset victim.

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).

Learner Tien, a 19-year-old qualifier from California, became the youngest American man to reach the Australian Open's third round since Pete Sampras in 1990, upsetting Daniil Medvedev in five sets Thursday.