American teenager Learner Tien takes out world No. 2 Alexander Zverev in Acapulco stunner

Last month, Learner Tien made a breakthrough run to the fourth round of the Australian Open as a qualifier, defeating No. 5-ranked Daniil Medvedev along the way for the first Top 5 win of his career.

In Acapulco tonight, he struck again.

The 19-year-old Californian has beaten another Top 5 player, this time Alexander Zverev, taking out the No. 2-ranked German in straight sets in the second round of the ATP 500 event, 6-3, 6-4.

With that victory, Tien becomes the youngest man to beat a Top 3 player since 2022, when Carlos Alcaraz—a younger 19 at the time—defeated a No. 3-ranked Zverev in the Madrid final.

More impressively, he becomes the youngest American man to beat a Top 3 player since all the way back in 2001, when Andy Roddick, who was 18 years old at the time, defeated a No. 1-ranked Gustavo Kuerten in the third round of the Masters 1000 event in Canada.

Tien was born four years later, in 2005.

After dropping the first set, it looked like Zverev might battle his way back for a three-set win—like he did in the previous round against Matteo Arnaldi—after building a 4-1 lead in the second set against Tien, even getting to deuce on his opponent's next service game.

But the American lefty dug out a hold for 2-4, broke back for 3-4 and actually ended up winning the last five games in a row to close it out.

At the end of the day Tien was just too solid, finishing with an almost even number of winners and unforced errors, 15 to 16.

Meanwhile, Zverev finished with 21 winners to 27 unforced errors, two thirds of those miscues (18) coming off his forehand side.

Tien is now 2-0 in his career against Top 5 players, his only previous meeting with a Top 5 player being the aforementioned win over Medvedev in Melbourne, and he's now through to the second ATP quarterfinal of his young career, having made the last eight at the ATP 250 event in Winston-Salem, North Carolina last summer.

Awaiting the No. 83-ranked Tien in the last eight in Acapulco will be a first-time meeting against No. 25-ranked Tomas Machac, a 7-6 (3), 6-1 winner over Daniel Altmaier in his second-round match.