Guardiola is preparing to take his side across the city to face the Red Devils in the Premier League on Saturday.
The Citizens are currently five points behind league leaders Chelsea and know defeat at Old Trafford could see them cut adrift in the race to land the title.
Ahead of the clash, Guardiola was asked whether he attempted to take Ronaldo to the Etihad Stadium before the transfer window closed in August.
But the City manager wasn’t in the mood to share that information.
“Normally I don’t talk about players for other clubs,” came Guardiola’s reply. “I’m sure Ronaldo is happy at United.”
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Ronaldo has scored nine goals in 12 games since arriving at United for his second stint and notched a brace in midweek against Atalanta as his stoppage-time effort at the end of the match rescued a point in the Champions League.
He is proving to be a consistent source of goals once again for United, although the forward has come in for criticism from a number of fans due to his moody demeanour when things haven’t gone his way.
But Ronaldo will be looking to silence his detractors against City and get on the scoresheet for a third consecutive time.
The forward’s final goal for the Red Devils before he left for Real Madrid in 2009 came against Man City and he will be looking to pick up from where he left off on Saturday.
“Maybe in the future we will buy a proper striker – a number nine who will score goals, who knows.
“We are who we are, we move forward in this sense – I spoke many times.
“We wanted to do it but could not do it – we have enough players.”