Teenage talent Learner Tien added another feather to his cap on Wednesday night at the Mexican Open. Tien stunned top seed Alexander Zverev in a late-night barn burner to register his second victory against a Top 5 player.

Tien won the first set 6-3 after surviving a Zverev barrage in the fifth game when he held from 15-40 down. The German responded by getting an early break in the second set and looked on course to level the match when he took a 4-2 lead.

But Tien had other ideas as his precise and powerful groundstrokes extracted enough errors from Zverev to turn the set on its head. From 2-4 down, he won four straight games to complete the upset on a bizarre night in Acapulco.

Tien Breaks 24-Year American Record With Zverev Win

The victory propelled the 19-year-old Tien to his first Tour-level quarterfinal. There was also a significant meaning to his massive win. Tien is the youngest American man to beat a top three player in an ATP tournament since 2001.

Former US Open champion Andy Roddick was 18 when he defeated world #1 Gustavo Kuerten in the third round of the National Bank Open in Canada 24 years ago. Back then, Tien was not yet born.

At this year’s Australian Open, Tien announced himself on the big stage with a rousing five-set win against former World #1 Daniil Medvedev for his maiden top five win.

Tien Emulates Legendary Jimmy Connors In A Key Stat

Tien had never faced a Top 5 player before this year, but he’s now faced that elite band in two tournaments this season and beaten them both at the first attempt (Medvedev and Zverev). It is pertinent to note that Medvedev was world #5 while competing in Melbourne.

#AMT2025 | @AbiertoTelcel @atptour @ATPMediaInfo pic.twitter.com/XYOsH27gzO

— OptaAce (@OptaAce) February 27, 2025

According to Opta, Tien–at 19 years and 87 days–is the youngest player to achieve this incredible milestone. Moreover, he joins retired legend Jimmy Connors as the second American in winning their first two matches against players ranked fifth or higher since the ATP rankings were first published over five decades ago. His reward will be a quarterfinal match against Tomas Machac on Thursday night.