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

World number two Alexander Zverev suffers a shock early exit from the Mexican Open with a straight-set defeat against teenage qualifier Learner Tien.

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.

Britain's Cameron Norrie loses in straight sets to American teen Learner Tien in the first round of the Mexican Open.

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.

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.

The up-and-coming Learner Tien defeated World No. 5 Daniil Medvedev at the Australian Open this year and will now be coming up against World No. 2 Alexander Zverev in Acapulco.