World No. 1 Aryna Sabalenka's grip on her top ranking and her US Open title defense appeared shaky after a stunning upset at the Cincinnati Open on Wednesday. The 28-year-old Belarusian lost to unseeded 20-year-old Czech player Sara Bejlek 7-6(7), 6-4 in the Round of 16, marking her worst defeat of the season.
This result follows a similar early exit at the Canadian Open two weeks prior, where Sabalenka was defeated by No. 16 Ekaterina Alexandrova. Bejlek's victory was her first against a top-10 opponent.
The loss in Cincinnati has direct implications for Sabalenka's world No. 1 ranking. If No. 2-ranked Elena Rybakina reaches the Cincinnati final, she will overtake Sabalenka. Rybakina had a quarterfinal match scheduled for Thursday night.
Commentators and fans expressed concern for Sabalenka, with some suggesting she has mentally checked out of tennis. Bastien Fachan, author of "Big 3," wrote on X that Sabalenka "lost sight of her identity" and has "mentally checked out of tennis."
Sabalenka's frustrations were visible during the first-set tiebreaker. After establishing a 5-1 lead, she lost three consecutive service games, allowing Bejlek to force a set point. During the tiebreaker, Sabalenka threw her racket, sending a string dampener flying across the court, which led to a brief search and questions about a potential time violation.
This summer hardcourt swing has been a stark contrast to Sabalenka's earlier success in 2026. She secured victories at the Indian Wells and Miami Open tournaments, part of the Sunshine Double. However, since March, she has not reached another final. Her Grand Slam performances have also faltered, with quarterfinal exits at Roland Garros and a fourth-round appearance at Wimbledon.
Following her Wimbledon loss, her earliest Grand Slam exit since the 2022 French Open, Sabalenka expressed a desire to "get completely drunk" and "forget about tennis."
Sabalenka, who favors hard courts and has won two Grand Slam titles at both the Australian Open and the US Open, has struggled to replicate her early-season form. Her recent struggles have left the women's field open, with Mirra Andreeva and Linda Nosková winning their first Grand Slam titles this year at Roland Garros and Wimbledon, respectively.
As of Thursday morning, Sabalenka was listed as a +320 favorite for the US Open title. The main draw of the US Open is scheduled to begin on August 30 in Queens.