Phil Foden struck twice, with Mateo Kovacic, Jeremy Doku, Erling Haaland and James McAtee also scoring on Sunday night.
Guardiola later said: "Long time it didn’t happen. We have got some good results lately.
“The players realised where we were, our standards lacked because it's not just winning titles, it is the joy to do your best. It doesn't matter if you’re a big actor in London or a little theatre in Sheffield - it doesn't matter.
"I think the players today proved many things and hopefully it can be the beginning of recognising ourselves of who we were.”
On Foden, he said: "One of the reasons he struggles, is Phil and many players were not there. Look at Kevin de Bruyne in the last three games, Kevin in his prime. We don't have that rhythm and step-by-step players come back.
"To get the best for the team they have to push each other and compete with each other. That couldn't happen this season as we have 13-14 players - no more than that."
On McAtee, Guardiola also stated: "He is such a good footballer and a lovely guy. Quite similar qualities as Phil.
“It is not easy when you don’t get many minutes for your confidence. Hopefully we can keep James for many years."