Osaka made 37 unforced errors in two sets and suffers her second consecutive early exit from a Grand Slam.
Two-time Grand Slam champion and world No. 2 Naomi Osaka is out on the first day of Wimbledon.
The reigning U.S. Open and Australian Open champion played a sloppy match and was defeated in the first round at the All England Club by unseeded Yulia Putintseva 7-6, 6-2. It's Osaka's second straight early exit from a Grand Slam after the 21-year-old lost in the third round of last month's French Open.
A devestated, emotional Osaka had to stop her press conference short after the loss on Monday.
"Can we stop?" she asked the moderator. "I feel like I'm about to cry."
Osaka, who has never made it past the third round at Wimbledon, seems to still be flummoxed by how to play on grass. She made 37 unforced errors—to Putintseva's seven—and looked generally uncomfortable all afternoon on Centre Court.
Her only other tournament on grass this year, the Nature Valley Classic, also ended with an early defeat to Putintseva—that one in the second round—who entered Wimbledon ranked 39th in the world.
Osaka is just 13-6 overall since winning the Australian Open and becoming world No. 1 in January. Shortly after that title, she split with coach Sascha Bajin, who she had worked with since 2017. Her post-Australia struggles saw her recently lose the top ranking to Ashleigh Barty, who won the French Open and the Nature Valley Classic back-to-back to take the No. 1 spot.
Osaka was the oddsmakers' sixth favorite to win the Wimbledon title, listed behind Barty, defending champion Angelique Kerber, Serena Williams, Karolina Pliskova and Petra Kvitova.
Putintseva, a 24-year-old from Kazakhstan, will play Switzerland's Viktorija Golubic in the second round on Wednesday.