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

Learner Tien and Alex Michelsen were born about 15 months apart and first crossed paths a decade ago when they were playing in Southern California tennis tournaments for kids. Tien, now 19, and Michelsen,

Corentin Moutet (No. 69 ranking) will face Learner Tien (No. 121) in the Round of 32 of the Australian Open on Friday, January 17.Moutet heads into the Round of 32 after winning in four sets, 4-6,

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 Learner Tien kept the teenage revolution going at the Australian Open by reaching the fourth round on Saturday after 38-year-old Gael Monfils had made a big statement for the old guard with a stunning win over fourth seed Taylor Fritz.

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

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 (No. 121) will meet Lorenzo Sonego (No. 55) in the Round of 16 at the Australian Open on Sunday,9.Sonego defeated Fabian Marozsan 6-7, 7-6, 6-1, 6-2 on Friday in the Round

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