Diego Costa (Atletico Madrid)
Well, it does not need a rocket scientist to work out what part of the pitch exactly the west London club have fallen short in this season, and especially after the two semi-final ties against the La Liga leaders.
And to that effect the Blues need to act fast in order to secure the Brazil-born striker’s signature for next season before any of their rivals steal the player from under Chelsea’s noses.
As after a campaign in which Costa has managed to find the back of the net on 27 occasions in just 33 Liga outings, the red-hot 25-year-old is just the sort of prolific and clinical marksman the club are in need of this summer.