Daniil Medvedev is out of the Australian Open after losing to American qualifier Learner Tien in the biggest upset of the tournament so far.

The 28-year-old was taken all the way to a deciding set by his teenage opponent, with the match going on for nearly five hours and ending just before 3:00am.

Medvedev went into the contest as the overwhelming favourite to win but ended up on the receiving end of a massive shock as Tien produced the display of his life to claim the spoils.

The tide began to turn after his outburst, with the former US Open champion finally settling in and playing closer to his best. It resulted in the match going to a fifth set, which was disrupted by a rain shower with the score deadlocked at five games each.

There were a huge number of empty seats inside the Margaret Court Arena near the end of the contest. Hordes of fans left as the clock ticked over into the early hours of the morning, but those who stayed were treated to a thrilling display of knife-edge tennis.

There was nothing to separate the two players, with a fifth-set tiebreak needed to determine the winner. It looked as though Medvedev would pull through but Tien managed to capitalise on his opponent’s mistakes to claim an incredible victory.

He was fairly nonchalant in his post-match interview despite having just secured the biggest win of his young career, saying: “I was definitely hoping it wasn’t going to go to a fifth-set tiebreaker, but either way, just really happy to get a win.

“I made it harder than it could have been but, you know, whatever. Losing the third was tough after playing for that long. It was a little disappointing to see a fourth but honestly, in the fourth set, I just had to pee so bad.

“I was just trying to finish it up fairly quick but I also wanted to start the fifth serving, so I scrapped out that game and it all worked out.”

The result saw Tien become the youngest man to reach the third round of the Australian Open since Pete Sampras in 1990. If he wins his next match against Corentin Moutet, he could enter the world’s top 100 for the very first time.