Paulo Costa has replied to a callout from Bogdan Guskov on social media. The Brazilian middleweight's response comes after Guskov publicly challenged him. Details of Costa's specific response are limited in the original post. The exchange represents the latest social media interaction between UFC fighters seeking high-profile matchups. Neither fighter has confirmed whether official negotiations are underway for a potential bout. This follows an earlier report that Guskov had declined a fight with another opponent.