There's never a bad time to tease your siblings. Naomi Osaka proved as much Wednesday, using her win over Serena Williams at the Australian Open to embarrass her sister on national television.
After meeting with Williams in the middle of the court, Osaka walked over and wrote a message on a camera before leaving the court. It was a lengthy message. Was she writing a heartfelt note to Williams? What about an encouraging message to young tennis players all around the world?
Nope. Osaka took the opportunity to tell her sister Mari to stop being weird.
— ESPN (@espn) February 18, 2021
The entire message read: "Mari, stop sending weird images in the groupchat!"
Sorry, Mari, now everyone thinks you're a weirdo. Don't send weird images to your sister who can communicate with millions of people whenever she desires.
Naomi Osaka moving on to Australian Open final
With the win, Osaka will have another opportunity to make fun of her sister soon. Osaka will move on to the Australian Open final, which will take place Saturday. She'll take on Jennifer Brady.
Osaka — who came into the Open as the No. 3 ranked women's singles player — will be the favorite over Brady — who ranked 22nd among women's singles players.
If she wins, Osaka would take home her fourth grand slam victory. Brady has never won a grand slam event.
More from Yahoo Sports: