Just 14 hours after Stan Wawrinka upset top seed Novak Djokovic, another Swiss player has beaten another No. 1 seed.
Defending U.S. Open champion Naomi Osaka suffered an upset straight-set loss (7-5, 6-4) to No. 13 Belinda Bencic in the fourth round on Monday, ending the world No. 1's hopes of winning her second-straight title in New York and third Grand Slam in the last 12 months.
Bencic, 22, jumped to an early 2-0 lead in the first set, generating four break points in the third game before Osaka fought back to win three straight games to take a 3-2 lead. Despite double faulting twice leading 6-5, Bencic fired a serve out wide that forced a missed return to clinch the set 7-5.
After a back-and-forth start to the second set, Bencic jumped to a 4-2 lead by winning a 21-shot rally with a forehand pass. Osaka held twice to make it 5-4 before Bencic sealed the win with a one-two punch, advancing to the U.S. Open quarterfinal for the first time since doing so as a 17-year-old in 2014.
Bencic finished the match with 29 winners to 12 unforced errors.
"I was so excited to come on the court. The challenge could not be bigger so I had to be on top of my game," Bencic said after the match. "I’m really pleased with how I played and how I managed my nerves in the end."
Monday's events marked only the fourth time in Open era that the No. 1 women's and men's seed suffered defeats before the quarterfinal.
Bencic will face No. 23 Donna Vekic in the quarters after the Croatian beat No. 26 Julia Goerges in a tight three-setter on Louis Armstrong.