"Wayne sacrificed himself in Barcelona," said Ferguson. "He had no problem when I told him what I wanted from him.
"Although he didn't play to his normal standard, he'll be playing in a different position on Tuesday. You will see a different Wayne Rooney then, believe me.
"We had to make up an extra midfield player in Barcelona because they played Iniesta wide left. To counter that, Wayne played wide on the right."
Although United were relieved to escape with a goalless draw, Ferguson admitted: "We could have done with an away goal but we didn't, so we have to win the game. It is straightforward. We'll be in our own ground with our support
so that will be a big advantage. History has shown that when we need a big performance and result at Old Trafford, especially in Europe, then we get one. And I believe we will beat Barcelona."