Pep Guardiola said Tuesday it was a "big mistake" to think about trophies so early in the season, after hungry Phil Foden said Manchester City were targeting a unique quadruple.
City completed a historic treble last season, winning the Premier League, FA Cup and Champions League.
England winger Foden, 23, has said the club are targeting a repeat of the treble or even a quadruple by adding the League Cup.
City have started the season in sparkling form, winning all six matches to top the Premier League and launching their Champions League defence in style.
But Guardiola attempted to temper the ambitions of his players as he prepares for a tough trip to Newcastle in the third round of the League Cup on Wednesday.
The Catalan was asked at his pre-match press conference about Foden's gung-ho statement.
"Phil is so young," he said. "He will understand with time. It's nice to have those ambitions but always I said to the players 'ambition is the next game'.
"So maybe in April, May if you are still in all competitions you can start to think about it but right now at the end of September to think about titles is a big mistake.
"But if he believes that, I will not be the guy to let him think the opposite."
Guardiola has hinted he could make wholesale changes for the Newcastle match, with injuries hitting hard.
But Newcastle boss Eddie Howe, who is himself without Joe Willock, Joelinton and Harvey Barnes, is refusing to be taken in by the City boss.
He said: "Pep is a manager who has won so much and he hasn't done that without giving everything to every moment to try and achieve that success. I've no doubt we will see the best Manchester City tomorrow."
Winger Barnes, who joined from relegated Leicester in July, could be facing months on the sidelines as he awaits a specialist's verdict on a foot injury he suffered in the 8-0 win at Sheffield United at the weekend.