They carried that form into competitive action and have proved unstoppable under the former Barcelona coach, thrashing Spurs 4-1 on Saturday to lead the Premier League table by 11 points.
And Guardiola, speaking after his team's latest victory at the Etihad Stadium, suggested the importance of overcoming Mauricio Pochettino's side in Nashville in July should not be underestimated.
"Tottenham last season, compared to Chelsea, played the best football in the Premier League," he said.
"Today [Saturday] I'm quite happy because I think this season has started going well from our game... against Tottenham in pre-season.
"Our first game in pre-season was against United and we lost and the second [sic] was against Tottenham and there we created maybe eight or nine or 10 chances to score lots of goals – we missed a lot – but there we saw altogether, not me, the players saw, ok that is the way we have to do it.
"Since then I think we maintained that level, with ups and downs of course, for example at Bournemouth we won in the last minute and Southampton we won in the last minute, but in general we maintained that level that we started against Tottenham in pre-season... and now we've maintained that level for three or four months and that's why we are so happy."
Guardiola also excused Sergio Aguero for an angry reaction to being substituted in the 58th minute against Tottenham, the Argentine throwing his gloves to the floor in disgust upon being withdrawn in favour of Gabriel Jesus.
"That's normal," the City coach said.
"The players want to play and I can understand him. He wants to play. He's a top player but in that moment I needed a little bit more energy with Gabriel in that position, so that's why I took that decision.
"Always I don't want to hurt the players, believe me. Always I understand them because I was a football player, they want to play, but I have to take the decisions... when I take a decision I think about many things, it's never personal because I trust a lot in these guys."