The Blues have already snapped up Cesc Fabregas from Barcelona and are hoping to make fellow Spain international Costa to their ranks.
The Atletico striker was in fine form last season for the La Liga champions but is expected to leave when he returns from the World Cup – which could be sooner than expected after Spain’s 5-1 thumping at the hands of the Netherlands on Friday.
Courtois has been on loan in the Spanish capital for the past three season but Mourinho is expecting the Belgian to challenge Petr Cech next season in West London.
“Costa is a player I want in my team,” Mourinho said.
“I’ve asked the club to bring him in and I am extremely confident that we are going to get him and he’ll end up signing for Chelsea”.
“Also, when the World Cup in Brazil is over, Courtois will be coming straight back to Stamford Bridge – end of story.”