Diego Costa: Player watch for the Chelsea striker against QPR Some questioned the £32m Jose Mourinho paid Atletico Madrid but Costa has been on fire. Strong, uncompromising and with an eye for goal, Mourinho sees him as the complete striker. Did the Spanish striker look fully fit? Understandably he did not look at his best after a four-game absence through injury and a bug. As it is Chelsea are forced to wrap him up in cotton wool to keep him playing and avoid hamstring surgery to correct ongoing problems. Who is Costa's best strike partner? There is no obvious candidate, with returning striker Didier Drogba a stand-in when required and Loïc Rémy out injured. Mourinho has tended to play Costa as a loan striker but reports suggest that he may enter the transfer market in January to sign another marksman. Can Chelsea win the title if he's injured? They secured his signature to land the title. His absence would be a crucial blow to Chelsea's title aspirations. At some point he is going to require surgery but Chelsea hope to delay it until the summer. In the event he does break down, it will pose a huge test for the Blues.