Ronaldo appeared dissatisfied when he was replaced in Portugal's 2-1 World Cup defeat to South Korea, though he indicated it had more do with the actions of an opponent than those of his coach .
Ronaldo was withdrawn in the 65th minute and replaced by Andre Silva with the scores level at 1-1 in the Group H finale.
Hwang Hee-chan's injury-time winner gave the Koreans victory to seal their progression to the last 16 alongside Portugal.
With Ronaldo having long since exited the stage, Portugal was unable to rescue anything from the game with the former Manchester United and Real Madrid star urging his teammates to learn from the poor performance.
He said of his reaction while leaving the field: "What happened was that before my departure, [a] Korean player told me to leave quickly. I told him to shut up.
"He is not the authority, he does not have to give his opinion, he would speed up the step if he were the referee. But there doesn't have to be any controversy.
"It's the heat of the game. Regardless of what happened, things stay on the field. We have to be united, we are in the next phase. All Portuguese have to be confident because we really want to progress.
"We knew in advance that we were qualified, there had to be almost a miracle for us not to progress [in] first. But I don't want to justify myself with that.
"We have to learn from these lessons when we don't play well. I hope we can learn from this defeat and we have to win the next game."
Santos said of Portugal's showing: "It's a disappointment. We did good things, but then we alternated with the least good. But it can be a warning. It can be a warning."
Portugal will face Group G runner-up Switzerland in the last 16 on Wednesday (AEDT).