Naomi Osaka has been eliminated from the 2019 US Open, which means Serena Williams is now the only Grand Slam winner left in the tournament

• Naomi Osaka's defense of her US Open title has come to an end as she's just been beaten by Belinda Bencic.
• Bencic beat Osaka in straight sets 7-5, 6-4, and now advances into Wednesday's quarterfinal against Donna Vekic.
• Osaka's elimination means there is now only one Grand Slam winner left in the women's singles bracket.
• 23-time Grand Slam champion Serena Williams, the second-highest seed, faces Wang Qiang on Tuesday.
• Fifth seed Elina Svitolina, the highest seed left in the tournament, plays Britain's number one Johanna Konta, also on Tuesday.
• Visit Business Insider's homepage for more stories.

Naomi Osaka's defense of her US Open women's singles title has come to an end as she's just been eliminated from the tournament by Belinda Bencic.

Osaka lost in straight sets 7-5, 6-4 at Flushing Meadows in Queens on Monday, and Bencic said after the match that she had to play her best tennis to advance into Wednesday's quarterfinals.

"I was so excited to come on the court," Bencic said, according to the New York Times.

Read more: Novak Djokovic apologized and said his injury 'hurt' after tennis fans mercilessly booed him off the US Open court

"I think the challenge cannot be bigger: against Naomi, a great player and who obviously won the US Open last year. I had to be on the top of my game. I'm very pleased with how I played and how I managed my nerves in the end.

"She has a lot of power, I was just trying to play it a little bit like chess, anticipate, and make a tactic on the court."

It was Bencic's third win of the year over Osaka, who recently attracted headlines for the way she defeated the 15-year-old American Cori "Coco" Gauff on Saturday.

But defeat to Bencic brings an end to her reign as champion, as the 22-year-old Swiss player now advances into Wednesday's quarterfinal where she faces Donna Vekic, 23.

Read more: Serena Williams' coach doesn't regret breaking the rules of tennis before her infamous 2018 US Open meltdown, and even says he'd 'do the same tomorrow'

Osaka's elimination means there is now only one Grand Slam winner remaining in the entire women's singles bracket, with 23-time Grand Slam champion Serena Williams playing Wang Qiang at the Arthur Ashe Stadium on Tuesday.

Williams, last year's finalist, is the second-highest seed, behind only fifth seed Elina Svitolina who plays the British number one Johanna Konta, also on Tuesday.