Sir Alex responded by throwing on Dimitar Berbatov for John O’Shea, forcing Ryan Giggs to move to left back.
“We took that risk, but it was worth it to get the three points,” he said.
It then appeared the manager was about to replace Tevez (the eventual match-winner) with winger Ji-sung Park.
“Maybe I was,” he said with a wry smile. “At that point I was thinking the match could end in a draw. We were a little worried about our lack of width and I wanted to get Wayne Rooney back in the middle.
“But Carlos scores important goals and he’s come up trumps again.”