The boss fielded players as young as 17 - in the shape of injury-time substitute Ravel Morrison - as the Reds knocked out Wolves at the end of a pulsating second period.
"It was a really good cup tie in the second half and I thought Wolves played their part, they played well," reflected Sir Alex.
"We played well too. I think the future's bright, I think everyone at the club is very positive about that. We work hard at producing young players and they're definitely, without doubt, the foundation of the next team."
Javier 'Chicharito' Hernandez is already a big hit in the current team, after coming on to score his third goal in three days and win the cup tie just when extra time was looming.
"We tend to build up heroes very quickly here but the boy's justifying the praise at the moment," the manager commented.
"He's such a good professional, the kid. He's first in and last out at the training ground every day and his goalscoring is getting him a lot of praise and credit and quite rightly.
"When he came on, you just knew that if he got a chance, he'd take it. It was a magnificent goal. He’s dummied the defender really well, shaped to shoot, pulled it round onto his left foot and it was a great finish.
"His touch, his control of the ball and his vision are all improving. That's simply because the training is intense. We care about our training and make sure players do improve."