Chelsea are set to make a late deadline day move for Atletico Madrid striker and Manchester United target Diego Costa, according to the Metro. The Brazil-born frontman has been consistently linked with Stamford Bridge throughout this transfer window. And despite assurances from Chelsea boss Jose Mourinho that Chelsea are not in the market for a striker, the report claims the Blues are ready to test Atletico's resolve with a dramatic late £30m offer. The Metro notes that Arsenal and Manchester United have both scouted Costa in the last month, but Chelsea are prepared to make their move. Mourinho clinched a deal for St Etienne defender Kurt Zouma earlier today, Chelsea's third deal of the window.