The champions were held to a frustrating goalless draw in front of a near-capacity and vociferous crowd, as Guardiola had called for, at the Etihad Stadium.
Guardiola issued a rallying cry to supporters in midweek, stating his side would be tired after their Champions League game against RB Leipzig and would need their energy.
“If we want to win here we have to have a perfect game and a perfect day. I think tactically we had a nearly perfect one but we needed a bit of luck to get such a penalty and this was not there.
“Everything was working fantastic. I must say I am very proud of what my team did today.”
Hasenhuttl admitted his heart was in his mouth after Sterling’s late strike but felt Saints deserved the point.
“We are always pushing out and I had the hope it was offside,” he said. “We deserved to get something today.”