Cori “Coco” Gauff’s incredible run at Wimbledon came to an end Monday with a fourth-round defeat to No. 7-ranked Simona Halep. The 15-year-old American won three matches before falling, 6-3, 6-3, to Halep, who won the 2018 French Open and was ranked No. 1 in the world as recently as January.

Gauff, the youngest player to ever qualify for Wimbledon, stunned the tennis world a week ago when she defeated Venus Williams, one of her idols, in the first round. She proceeded to knock out Magdaléna Rybáriková and Polona Hercog in the next two rounds to set up her match with Halep.

Her third-round match against Hercog drew so much attention it was played at Centre Court.

Halep proved to be too much for Gauff in her fourth match at All England Club, however. The Romanian star saw little trouble in taking down the teenage phenom in straight sets, showing why she’s a contender to win the championship.

Two Americans, Serena Williams and Alison Riske, will advance to the quarterfinals, but only one will reach the semifinals given they’re facing each other. Riske knocked out world No. 1 Ashleigh Barty in their fourth-round match.