Title holder Naomi Osaka has crashed out of the US Open with a 7-5 6-4 defeat to Belinda Bencic.

Osaka will also lose the world No.1 spot to Ashleigh Barty after the result on Monday.

The 21-year-old found no answer to the accuracy and consistency of the 13th-seeded Swiss as she lost for the third time this year to Bencic in 1 hour and 26 minutes under the closed roof at Arthur Ashe Stadium on a rainy day.

“The challenge cannot be bigger playing Naomi,” Bencic said. “She has a lot of power, me not so much. I play like chess and anticipate.”

Bencic broke Osaka at love in the fifth game of the second set on a double fault from the Japanese.

Two days after her emotional win over Coco Gauff, Osaka called for the trainer at the following changeover, was given a pill, but was not able to turn around the match again as Bencic served out the match to love.

The defeat lets her slip to fourth in the rankings, according to the WTA, with Barty returning to the top, ahead of Karolina Pliskova and Simona Halep – although all three of them are also already out in New York.

Osaka’s elimination also means that the US Open are without both top seeds in the quarter-finals for the first time in the Open era which started in 1968.