Darron Gibson grabbed both the goals in the 2-0 victory for a United side that was made up in a similar way to the side that came under much criticism for losing to Besikas in the Champions League.
Ferguson said of Gibson:"His second was a fantastic goal – great movement and work off the ball and a great finish.
"Darron is the one player at our club who can always get a goal from outside the box. He's got tremendous shooting power as he showed tonight.
"I thought we were fortunate in the first half. Tottenham dominated the first half-an-hour or so of the game and could have been two or three up.
"We had to defend really well – Tomasz (Kuszczak) made a good save from Defoe and Vidic had a couple of great tackles which kept us in it. We took time to get going, but when we got the first goal we improved.
"We played more controlled football in the second half and Anderson and Gibson really started to impose themselves on the game.
"We've ended up comfortable winners in the end, but we can't dismiss the fact we were playing a very good team. We're very pleased to be in the semi-finals."