City threw the proverbial kitchen sink at the visitors, after they had taken an early lead through James Ward-Prowse, but were met by a wall of black shirts time and time again.
The pressure finally told in the 70th minute, Sergio Aguero getting the galvanising goal before Kyle Walker sent the Etihad Stadium into raptures with his strike three minutes from time.
It was a victory conjured out of desire and determination rather than free flowing football, but Guardiola was left delighted by his players’ grit.
“We did everything,” he said.
“It was so difficult to attack when they defend with 11 players. We did everything we could and in the end our intensity and our players paid off. We made a good comeback.
“We were so patient. We were aggressive. The rhythm was high from the first minute. Big compliments to the team it was not easy and we did it.”
On a tense afternoon for everyone of a sky blue persuasion, Guardiola cut an animated figure on the touchline.
When the ball went out of play near the dugout, it was the Catalan who got it back in his players’ hands and if his urgency was to inspire, it was because he could see how difficult the challenge in front of his players was proving to be.
Southampton were camped on the edge of their box for long periods and it forced City to, uncharacteristically, pepper the box with more than 40 crosses, but the man who has wowed the world with his brand of beautiful football had no complaints.
“They defended with 11 players,” added Guardiola.
“They didn’t allow you to go inside. They allowed you to go outside. There wasn't any space. [Danny] Ings and [Nathan] Redmond defended the 18-yard box.
“We needed people in the box. It was almost impossible. They were so close.
“The difference between the back five was so close. There was no space. We made the space big because we had the wingers and full-backs wide.
“We were patient, but we were constant. That’s why we made the comeback.”