Diego Costa has slapped in a transfer request at Chelsea.

El Mundo Deportivo says Costa has handed Chelsea a formal transfer request.

Costa is keen to return to Atletico Madrid and has tried to accelerate a move away from Stamford Bridge by officially telling the Chelsea hierarchy that he wants to leave.

But Antonio Conte wants to keep Costa in his squad.

Atletico president Enrique Cerezo has talked up the prospect of re-signing the striker this summer.