Sir Alex Ferguson believes Wayne Rooney could match the 42 goals Cristiano Ronaldo provided for Manchester United in 2008 after the England striker reached the 30 mark with a double in the Champions League humbling of AC Milan.

Rooney, who had also scored twice in the 3-2 first leg win, laid the foundations for a 4-0 win on a night that United boss Ferguson described as one of the most satisfying of his illustrious managerial career.

"When I think that we've beaten Milan 4-0 - not many teams have ever done that, if any," the Scot declared. "It was a fantastic night."

It was the first time United had eliminated their opponents for the first time in five attempts since two of European football's iconic institutions first met, 52 years ago.

Ferguson said: "I said it was a landmark victory when we beat them over there. I regard Milan as a great European example for us and that makes me particularly proud that we managed to beat that great team."

Rooney's early header was followed by a strike in the first minute of the second half which broke Milan's spirit and further goals from Park Ji-Sung and Darren Fletcher ensured it was an unhappy return to Old Trafford for David Beckham.

"I think the second goal was decisive," Ferguson said.

"We were able to relax and play good football. Milan were forced to try and attack and left themselves a little bit open. It was a difficult night for them after that."