It's been 11 years since the New Yorker first qualified for the US Open. (AP)

#FunSizeOnTheRise still applies at the US Open, where 5'5" world No. 141 Kristie Ahn is into the final 16, with a 6-3, 7-5 win over Jelena Ostapenko on Grandstand on Saturday. Her match point was sealed with an ace.

"It was exciting, because I hit an ace, which I never do," Ahn said. "I could finally let my emotions get to me. The crowd roared. It was such a cool environment. Yeah, when I looked back, I was like, You cried, what a little baby. All my friends told me they cried, too, so I guess that's okay."

The WTA doesn't even list her height; the 5'5" is according to Stanford, where she was on the 2013 NCAA Championship–winning team.

The Grand Slam breakthrough has been a long time coming: Ahn made her first US Open by winning three qualifying matches in 2008, when she was 16. She wound up losing in the first round, to Dinara Safina, and she'd go 11 more years without recording a main-draw major win. Despite that, she still got mixed up defending US Open champion Naomi Osaka. 

Then this week everything changed, when Ahn—winner of the USTA's US Open Wild Card Challenge—scored a 7-5, 6-2 first-round win over Cincinnati finalist and 2004 US Open champion Svetlana Kuznetsova. 

She then beat 20-year-old qualifier Anna Kalinskaya and 2017 Roland Garros champion Ostapenko, making it to Round 4 without dropping a single set. She next faces her first seeded opponent of the tournament, No. 25 seed Elise Mertens. 

Ahn, who started the year ranked No. 200, is now projected to break into the Top 100. Eleven years is a long time to wait for your breakthrough season, but right now, it all feels worth it. 

Wake up every morning with Tennis Channel Live at the US Open, starting at 8 a.m. ET. For three hours leading up to the start of play, Tennis Channel's team will break down upcoming matches, review tournament storylines and focus on everything Flushing Meadows.

Tennis Channel's encore, all-night match coverage will begin every evening at 11 p.m. ET, with the exception of earlier starts on Saturday and Sunday of championship weekend.