The 28-year Spain striker is expected to leave Stamford Bridge this summer after reportedly being texted by Conte that he is longer wanted at the club.
And any hope of saving his career at the club appears to have gone up in smoke after the player posted a picture on Instagram of him partying in Brazil wearing an Atletico shirt.
To add insult to injury, the volatile centre-forward also threw shade at manager Conte in a reply to Cesc Fabregas’ comment on his live video.
‘Give Conte a hug,’ Costa said.
The post has since been deleted.
Costa has had a fractious relationship with the Chelsea manager since the Italian’s arrival in West London and looked destined to leave in January after his attitude was questioned amid interest from Chinese club Tianjin Quanjian.