Chelsea boss Guus Hiddink says Ghanaian Michael Essien's performance was the key to their shock 3-1 Champions League victory at Liverpool.He said: "Elsewhere we worked hard to stop their weapons, (Steven) Gerrard and Torres, and the passing triangle they use with the right-back, (Alvaro) Arbeloa."Michael Essien was the key for us in midfield. He did not only follow Gerrard everywhere, but was able to be the starting point to many of our attacks."We also felt we could have some success attacking at corners with the way they use their zonal marking. We managed some real benefits from that."Source: Ghanasoccernet.com