There are three American men aged 23 and under in the second week of a Grand Slam. That hasn't happened since 2003

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.

Two of four American men still playing in Melbourne, Irvine native Tien, 19, and Aliso Viejo native Michelsen, 20, became friends on the youth tennis circuit

Learner Tien has stunned the tennis world, claiming an upset victory over Daniil Medvedev at the Australian Open.

Learner Tien has become the youngest American man to reach the Australian Open’s third round since Pete Sampras in 1990.

Learner Tien, a 19-year-old qualifier from California, notched the biggest upset of the 2025 Australian Open to date by beating No. 5 seed and 2024 finalist, Daniil Medvedev, in five sets. Tien won 6-3,

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

Two friends from California, Learner Tien and Alex Michelsen, have both reached the fourth round at the Australian Open