Rooney has been in stellar touch for the Barclays Premier League champions this season netting 32 goals, and at times single-handedly keeping United's season alive.
"The most important player is Wayne Rooney," the England manager said. "He scores lots of goals; he finishes everything.
"Players need time. Rooney started at Everton at 16 and he has matured. Right now, his form is incredible and I hope he can maintain that level until South Africa.
"There are three players who are on a different level at the moment. One is [Lionel] Messi, one is Cristiano Ronaldo and one is Rooney. They are a step above everyone else in the world."