Nemanja Matic’s strike consigned the defending champions to a 1-0 defeat in the second leg at the Etihad Stadium, but our 3-1 win at Old Trafford three weeks ago ensured we progressed with a 3-2 aggregate victory.
Guardiola was satisfied with his players' display in the return fixture and delighted with their performance across the whole tie.
“Today we met an incredible, physical side,” he said afterwards.
“Their goal was a set-piece and the first time they shot on target. In the second half they shot once and no more than that.
“I am really pleased. For the 180 minutes we played in both games, we were better. I am so satisfied with the way we played and with the problems we have in the back four, with the injuries we have.
“I’m very pleased to be in the final for a third year in a row.”
Guardiola confirmed Claudio Bravo will retain his place in goal for the showpiece game against Aston Villa on Sunday 1 March, but is unclear as to how injuries will affect this weekend’s game against Tottenham Hotspur.
Fernandinho, Aymeric Laporte and Benjamin Mendy all missed the semi-final clash and remain doubts for the trip to London.
In their absence, Kyle Walker, Nicolas Otamendi and Joao Cancelo performed well in a new-look three-man defence the Catalan admitted was designed to deal with United’s pace on the counter-attack.
Though City spurned a host of chances, the defensive trio proved effective as they restricted the Reds' in the final third and Guardiola feels City’s third straight League Cup final is proof of how seriously we take each and every competition.
“When people talk about complacency because of what we have won; we would not be able to make the final three years in a row,” he added.
“Normally when you win a lot, this competition doesn’t matter. That’s never happened with my team. We can lose, but it [complaceny] will never happen. It's never happened in my eleven or twelve years as a manger.
“I am incredibly delighted for all of us because it doesn’t matter what competition we play, we try to win. I’m happy to be at Wembley against a historical team like Aston Villa.”