The demand to see Serena Williams continue her final U.S. Open run has resulted in some insane ticket prices for Friday's match ... with some seats tripling in value!!
TMZ Sports has learned ... fans rushed to buy their spot at Arthur Ashe Stadium for Williams' 3rd-round match against Ajla Tomljanoviu0107 immediately after the GOAT's win on Wednesday.
Considering it could be Serena's last singles match of her career, seats that were originally MUCH cheaper on Wednesday will now cost a pretty penny.