He watched with delight as goals from Jonny Evans, Patrice Evra and Tom Cleverley capped a fine display in the north east, where the Reds were disappointed to lose by the same scoreline in January last season.
"It was a great result to come here and win 3-0 against a very powerful and aggressive Newcastle team," Sir Alex told Sky Sports. "You have to really perform and make sure you keep control of the game and I think we did that for most of the time.
"We were terrific in the second half against Tottenham, it was an absolutely brilliant performance but the first half spoiled the whole day. Whereas today we were really on top of our game in terms of concentration, determination and all of the things you want to see in a team that is going to win.
"I think concentration is important at this level and we concentrated on the way we played in the first 20 minutes. It's strange that we played so much good football and made good openings, but we scored from two set pieces which is unusual for us.
"Patrice Evra has only scored four goals and I think Jonny Evans has only got two goals. But you take it because winning these games is important and all in all, I thought the football was really good and the concentration was terrific and the determination was there.
"I think there was pressure [on us] because you don't want to fall too far behind. If we hadn't won today we would have been seven points behind Chelsea. We are in the frame and we are still there. Obviously, every game is important now because we want to stay up there and hopefully we can do that."