The world number two Alexander Zverev suffered an outing at the start of the Mexican Open shock with a direct defeat against the adolescent qualifier, Tien.
The Australian Open finalist, Zverev, Acapulco’s seeded, achieved an unusual performance waterproof for errors while American Tien won 6-3 6-4.
Tien, 19, defeated Briton Cameron Norrie during the previous round and will face the Czech Tomas Machac in the quarterfinals.
“I just went and tried to control my side of the court,” said yours.
“Obviously, I knew it was going to be a difficult match. To pass good … I think I focus on what I can control and keep my composure as best I can prove to be very far away.”
Tien is the youngest American to record a victory against an opponent among the first three since Andy Roddick in 2001.
He had a few memorable months, reaching the final in the next ATP final in December before going to the fourth round to Australian Open in January.
Zverev is one of the six seeds to leave the competition in the second round.
Casper Ruud, Tommy Paul and Holger Rune all withdrew because of a stomach insect, while Ben Shelton and Frances Tiafoe were beaten by David Goffin and Alejandro Davidovich Fokina respectively.
Ruud finished second in the ATP 500 event in 2024, but the second seeded did not reach the court for his meeting with the local favorite Rodrigo Pacheco Mendez.
“I hoped to overcome this stomach disease that arose yesterday,” said Ruud on Instagram.
“Hoping to come back stronger in a few days and return to Mexico here next year.”
Rune, fourth strike, started his match against Brandon Nakashima but had to retire while dragging 3-0 in the first set.
“Furious and so sad at the same time. Had food poisoning and could not play today,” said Rune on X.
“One of my favorite places is Mexico and I love this tournament. Absolutely not as I wanted.”
