Khamzat Chimaev has fired back at Paulo Costa after the Brazilian accused him of DMing his partner.Chimaev is set to challenge reigning middleweight champion Dricus du Plessis for the title at UFC 319 next month. Meanwhile, Costa secured a unanimous decision victory in the co-main event of UFC 318 against Roman Kopylov. The two have engaged in frequent back-and-forths on social media over the years.'The Eraser' stated in his UFC 318 post-fight interview that he wants to face Chimaev next, claiming he hates him for allegedly sending a message to his partner. Costa followed up with a series of insults, calling Chimaev a "coward."In response, 'Borz' fired back on X, insisting it was the other way around and that it was the Brazilian’s partner who messaged him."It was she who wrote to me habibi 🤣🤣🤣."Check out Khamzat Chimaev's comments below:'Borz' and Costa nearly engaged in a physical altercation at the UFC Performance Institute in Las Vegas ahead of UFC 279 in 2022. Chimaev's team had to separate the two to avoid an all-out brawl.Costa has stated on multiple instances that the Chechen-born fighter has repeatedly declined to fight him and labeled him "scared." The two were scheduled to lock horns at UFC 294. However, Costa had to withdraw due to an elbow infection. Chimaev instead fought Kamaru Usman and won by majority decision.