"There are a lot of top sides that can be very, very strong," said the boss.
"We can always talk about the top four, but Manchester City are doing a very good job and have bought some excellent players. They will be a big problem to us, but mainly to United, as they are their neighbours.
"I can understand why Mr Ferguson at Manchester United is a little bit worried.
"I don't know too many managers happy with the money that they have to spend. There are two or three clubs around the world that have big, big money, but the rest of the managers I am sure will ask for more money.
"It is not impacting on my commitment. Always when you have some difficult, you have to work harder.
"We were doing a good job with the options that we had. We are happy with the additions, and if they can settle down quickly I will be really pleased because the rest of the squad is more or less the same."