The Irish striker declared: "We know that at a club as big as Sunderland, everyone has to expect competition for places.
"I have seen a lot of new strikers come to the club since I first joined, but I think that has been good for me. You learn from other players and it avoids any complacency.
"Certainly if you look around the squad these days, we are getting to the stage where there's top-quality competition for every single place in the side.
"And that can only be good for Sunderland Football Club."