American Alison Riske upset World No. 1 Ashleigh Barty in a fourth-round match at Wimbledon on Monday.
Barty won 15 matches in a row and entered with a chance to win consecutive Grand Slam titles following a French Open championship. She won the first set, but Riske stormed back to take down the Australian 3-6, 6-2, 6-3.
"I haven't been starting out fantastic in all my matches, but I knew I had the confidence that if I could manage my service games I was going to get looks on her serve," said Riske, who entered the tournament unseeded and ranked 55th in the world. "I had to play aggressive. I had to take it to Ash."
Riske advances to face Serena Williams on Tuesday in the Wimbledon quarterfinals. Williams downed Carla Suarez Navarro 6-2, 6-2 on Monday in a dominant 64-minute exercise.
The 37-year-old Williams advanced to the quarterfinals at Wimbledon for the 14th time.
"Last time I played a fellow American I lost so I want to do well this time," Williams said of meeting Riske. "She is great on the grass. I will be ready for it."