Juventus coach Massimiliano Allegri confirmed hours earlier that Ronaldo had informed him of his intention to leave the Serie A club.
Ronaldo's agent Jorge Mendes had reportedly approached City, who missed out on signing Harry Kane after the England captain elected to stay at Tottenham.
Reports on Thursday claimed personal terms between City and Ronaldo had been agreed and the transfer seemed to be edging closer when the 36-year-old was pictured leaving Juve's training ground, seemingly for the final time.
However, in a remarkable twist, Ronaldo's former club and City's rivals Manchester United have now reportedly entered the running and, in his pre-match news conference ahead of this weekend's clash with Wolves, Red Devils boss Ole Gunnar Solskjaer suggested a deal could happen.
While Solskjaer's comments became public, Guardiola faced the media prior to City's clash with Arsenal on Saturday, and he claimed Ronaldo would ultimately make the final call on his future.
Shortly after Guardiola's news conference had concluded, the BBC said City had pulled out of the deal altogether.
"I cannot say much. Harry Kane announced that he's continuing with his club, an exceptional club like Tottenham," Guardiola told reporters.
"Cristiano, I think he's a Juventus player, I cannot add anything else. All I can say in these three or four days is that everything can happen.
"But in my personal view, there are a few players, and I think Cristiano is included and [Lionel] Messi of course, that they decide where they want to play. In that position [attack], right now, this is my feeling, I am more than delighted with the squad that I have and I think it will stay the same."
Asked if he would be able to coach Ronaldo after spending so much time hailing his former player Messi as the world's best, Guardiola added: "I say the same, Cristiano will decide where he wants to play, not Manchester City, not myself, there are many things but right now it looks far, far away.
"This is a difficult press conference, tomorrow we have an incredibly important game ahead of us, but now it is about other terms, other issues.
"We are incredibly grateful to have enjoyed the best two players we have seen probably in the past 20, 30 years, like these two guys have done, in world football, we can only say thank you.
"The Argentine and the Portuguese guy were amazing in every single season, in different clubs, especially Messi just at Barcelona but now in France. What they have done, we will not watch something similar in the future.
"I'm incredibly happy with the squad I have. More than satisfied. We are the same guys except one player has left, Sergio [Aguero], and Jack [Grealish] arrived. I am focused on the players I have. These type of players decide.
"Messi, he decided himself where he wanted to play. He decided Paris, he went to Paris. These players decide. They know the law, their goal. After that there are situations I cannot control, it's not my business. I am focused on what we have to do and the players we have right now."
The Kane saga has dragged on throughout the transfer window. Multiple reports have claimed Tottenham turned down a City offer for their talisman back in June, a bid which was said to be in the region of £100million.
Guardiola, however, said otherwise.
"The club did absolutely everything. We didn't talk with Tottenham – not even one offer – because they did not want to negotiate," Guardiola said.
"When one team doesn't want to negotiate, there is nothing to say. It is understandable so Tottenham they didn't want to talk, we didn't talk, that's all.
"Maybe they opened the door and they say we want for Harry Kane £200m. We are not going to pay £200m, for one reason, we do not have it, that's why we do not do it.
"We tried to open the door to negotiate and the big master of negotiations Mr Daniel Levy, he knows everything, so we could not do it. He [Kane] is a Tottenham Hotspur player and I wish him all the best in the last years of his career doing well in London."
Guardiola also confirmed City – who responded to an opening-day defeat to Spurs by thrashing Norwich City last time out – would be once again without Kevin De Bruyne for the meeting with Arsenal.