Daniil Medvedev learned a lesson he won’t soon forget at the Australian Open, courtesy of American teenager Learner Tien.

The 19-year-old held off a what would have been an epic comeback to score the biggest win of his young career, emerging from qualifying to stun the three-time finalist, 6-3, 7-6 (4), 6-7 (8), 1-6, 7-6 (7) and reach the third round—wrapping up the four-hour, 49-minute victory just before 3AM, local time.

“I know I made it a lot harder than it could have been but, you know, whatever!” the tired American joked on court.

A native of Irvine, California, the left-handed Tien had been a formidable junior, reaching the boy’s singles finals at both the Australian and US Open in 2023—losing the latter to none other than Joao Fonseca, who scored an upset of his own in the first round over No. 9 seed Andrey Rublev.

Tien went on to finish runner-up to Fonseca at last year’s Next Gen ATP Finals, having defeated all Top 3 seeds in Arthur Fils, Alex Michelsen, and Jakub Mensik along the way. The December result set himself up for a strong start to 2025: after winning three matches in qualifying, he won his first Grand Slam main-draw match over Camilo Ugo Carabelli to draw Medvedev for his highest-profile match yet.