"We are getting better with every game and we will reach our peak very soon," he told The Sun.
"The arrival of Dimitar Berbatov has given us even more firepower going forward.
"He's a great player and he always caused us a lot of problems when he was with Spurs.
"Fortunately, he's with us now. I think we got something different with him, another option up front. With Berbatov, Carlos Tevez, Cristiano Ronaldo and Wayne Rooney, we have four players who can change the course of the game single-handed."