Learner Tien celebrated his shock Australian Open victory over three-times runner-up Daniil Medvedev in true teenage fashion, seeking out a well-earned pizza after edging a five-set thriller to progress to the third round.

Learner Tien pulled off a massive upset against Daniil Medvedev at the Australian Open. So, who is Tien, the 19-year-old out of California?

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).