Naomi Osaka just made one young fan's day at the U.S. Open on Monday ... by gifting her a collectible Olympics pin as a "thank you" for showing so much support during her first-round match!!
The 23-year-old superstar advanced to the second round after winning in straight sets just hours ago ... and the little girl was cheering for her the entire time!!
Osaka -- who had an early exit from the 2020 Olympic Games -- said she had a few trading pins left over from her time in Tokyo ... so she decided to give an extra to her biggest fan in the stands!!
"I just heard her when I was playing my match and she was so cute."@naomiosaka shared a moment with a young fan and gave her an Olympic pin after the match ❤️ 🥺 pic.twitter.com/s9P9qs2dHV
— ESPN (@espn) August 31, 2021
FYI -- Olympic pin trading is a tradition that goes back more than a hundred years ... with athletes, reporters and fans all swapping the little items during the Summer and Winter Games.
Osaka was asked about the gesture in her post-match interview ... saying, "I just heard her when I was playing my match and she was so cute."
"So, thank you for cheering me on!"
The camera then showed the fan smiling from ear-to-ear -- at least, we're assuming, 'cause the whole mask situation -- and waving back at Osaka.
"I thought it would be a nice little memory," the #3-ranked player added.
As for the match, Osaka beat Marie Bouzková 6-4, 6-1 ... and will face off against Olga Danilović on Wednesday.