Guardiola guards against complacency after Man City's perfect start
The defending champions have won all five games so far in the Premier League and are the only team with a 100 per cent record.
They also clinched the UEFA Super Cup against Sevilla on penalties and made a winning start to their Champions League campaign, with a 3-1 win over Red Star Belgrade in midweek.
But Guardiola said he was keeping his feet on the ground despite the flying start, pointing to his first season in charge at the Etihad Stadium in 2016/17.
"When we arrived here seven or eight years ago we made six from six (at the start of the season) and we finished third. It's just the beginning," Guardiola said.
England winger Jack Grealish could return for Saturday's home game against Nottingham Forest in the Premier League.
Grealish has missed the treble winners' past three games with a knee injury and was also unavailable for international duty earlier this month.
The 28-year-old is now back in training, easing Guardiola's injury concerns after Bernardo Silva this week joined a casualty list that also includes Kevin De Bruyne, John Stones and Mateo Kovacic.
"We need the injured players back because we have a lot of games and we cannot play with the same players," said the City boss.
"Jack is coming back. He has trained well and maybe he will be ready for some minutes. Kova is almost there, he's in the last part of the recovery but now we've lost Bernardo. John and Kevin are still out."
Guardiola has given little information on the nature of Silva's problem other than to confirm he faces a short spell on the sidelines.
"He has a little injury," he said. "It is nothing much. The clinical development is good but it could be one week, 10 days, two weeks that he will be out."
Guardiola said he was wary of the challenge from Steve Cooper's eighth-placed Forest, who held his side to a 1-1 draw at their own ground in February.
"They are physical and well-organised," he said. "We have to be careful but we are optimistic we can do what we have to do, with our people, to make the sixth win in a row."
