Naomi Osaka considering break from tennis after U.S. Open loss to Leylah Fernandez

Fernandez's win over Osaka at Arthur Ashe Stadium was the biggest of her career. After the 18-year-old fell in a tight first set, she got Osaka in a tiebreaker in the second and whipped through the third after Osaka began getting frustrated. 

Fernandez was the second 18-year-old to knock off a No. 3 seed at the U.S. Open on Friday, joining Spain's Carlos Alcaraz, who beat Stefano Tsitsipas. 

Osaka, who has lost her past three tournaments in the third round, has had a challenging year battling mental health issues. 

First, she withdrew from the French Open in May after refusing to speak with the media due to mental health concerns that plagued her. She then sat out Wimbledon and didn't return to the court until this summer's Tokyo Olympics.

After her first-round victory over Zheng Saisai at the Olympics, Osaka said she felt "refreshed" and "happy again." But during last month's Western & Southern Open, she broke down in tears after returning to do a formal news conference when asked about her relationship with the media. 

Many athletes came to support Osaka when she announced she had been dealing with mental health issues earlier this summer, including NASCAR driver Bubba Wallace, who said he could relate to what the tennis star was going through.