American teenager Learner Tien beat top-seeded Alexander Zverev 6-3, 6-4 to move into the quarterfinals of the Mexican Open in Acapulco.

Zverev, the top seed at the Acapulco Open, went down 6-3 6-4 to the 19-year-old American on Wednesday. Tien, who claimed a big win over Daniil Medvedev en route to reaching the fourth round at the Australian Open in January, came from 1-4 down to win the second set – and the match – by reeling off five straight games.

Britain's Cameron Norrie has been beaten by teenage American qualifier Learner Tien in the opening round of the Mexican Open in Acapulco.Norrie, who is now 74th in the world, was beaten 7-6 (7-5) 6-3 by the 19-year-old,

Australian Open finalist Alexander Zverev suffered another setback when he was beaten 6-3, 6-4 by American qualifier Learner Tien in Acapulco. Top seed Zverev lost the last five games from 4-1 up in the second set to crash out in the last 16 match in 1 hour 26 minutes on Wednesday night.

Learner Tien, a 19-year-old from California, took down top-seeded Alexander Zverev 6-3, 6-4 to advance to the Acapulco Open quarterfinals.