Fabregas has been linked with a return to Spain in recent months.
He said: “When people think about Arsenal they talk about Emmanuel Adebayor and Robin van Persie but for me the key player for them is Fabregas.
“The young Spaniard is a fabulous player and key to the team. They are a very offensive outfit but they need a creator and Fabregas does that, as well as defend well.
“Fabregas is the player we will have to watch the most in this game because it is one we need to win.
“He would be a great loss to Arsenal if he ever left the club.”