The Spaniard, who moved to Stamford Bridge from Atletico Madrid, scored on his Premier League debut in last night's 3-1 win over Burnley.
The Belgian told the club's website: "They are all very good. Diego Costa is a striker who can score every time and Cesc Fabregas, who has played in the Premier League before, did very well.
"Diego can score and that is good for me, now I can concentrate on making passes for him. I don't think Thibaut [Courtois] could touch the ball for the first goal, but he had other things to do in the game and he did well. It was good for his first game in England."
Chelsea will face Leicester City on Saturday.