The former United captain added that the Chilean's traits will set Sanchez up for a fantastic run in Jose Mourinho's team.
"For me he's the perfect player for Manchester United. He's got aggression, he's got passion, desire and you can see he's a winner," Rooney said. "They are the players you want, almost like when Tevez joined United.
"Those players lift the other players and get an extra 10% [out] of the players around him. I think Sanchez will do that.
"I think that's what Manchester United have lacked, players around [Romelu] Lukaku who are going to push him on as well and try to help him get a bit more freedom and score more goals."
Sanchez scored his first goal for the Red Devils in last Saturday's 2-0 victory over Huddersfield Town.