Pep Guardiola says any club would "tremble" if Real Madrid or Barcelona enquired about one of their star players, amid speculation linking Raheem Sterling with Los Blancos.
In an interview with Spanish publication AS on Friday, City forward Sterling spoke of his admiration for Madrid following rumours of a potential move to the Santiago Bernabeu.
The England international was also pictured holding up the shirts of both City and Madrid, who meet in the Champions League last 16 next week.
In a news conference ahead of City's Premier League clash with third-placed Leicester City, Guardiola insisted he has no doubt over Sterling's commitment.
However, he conceded all clubs have to worry should Madrid or their LaLiga rivals Barcelona come calling.
"All the clubs have to know that when Real Madrid or Barcelona knock on the door, the other clubs must tremble, they will be a little bit in trouble," Guardiola told reporters.
"Barcelona and Madrid are maybe the strongest and most powerful teams in terms of history and how good they are. That is normal and I understand completely.
"But on the same point, you just see the commitment from Raheem, every single day when he arrives. He's never injured.
"His commitment in every game, offensively and defensively, so he's one of the best players in the world and it's normal that big clubs see his desire for the team.
"I don't know if Madrid or Barcelona called his agent, [but] I don't have any doubts about the commitment Raheem and the other ones have had from the first day to the last day."
Guardiola himself has been linked with leaving City after the club was handed a two-year ban from the Champions League by UEFA for a breach of Financial Fair Play (FFP) regulations.
With City in the process of lodging an appeal after denying UEFA's claims, Guardiola swiftly moved to dismiss reports of a potential exit and reiterated his commitment to City once more on Friday.
"My happiness. I'm looking for my happiness, that's the only thing I'm looking for," Guardiola said when asked if he would consider staying beyond the expiration of his current deal, which runs out at the end of next season.
"I'm working with exceptional players especially and I have the feeling that they follow us 100 per cent, knowing how it's not easy working with us and with me, but I'm happy.
"That is the only reason why, when I move on always it's because I am thinking I can be happier than the place that I was before. That is the only reason.
"We have got incredible owners and a good relationship, so I think it will not be a problem to understand both sides if we decide to stay three more years or stay in the time we are together."