Ronaldo netted the victor of the game with a first-half header to send the European champions to the top of Group A and all but secure a place in next week's semi-finals.
Mexico needs at least a draw in Saturday's game in Kazan to secure a spot in the semifinals of the eight-nation tournament.
Santos told a pre-match news conference in St Petersburg that he would similarly rotate his starting XI but refused to confirm whether that means time on the bench for Ronaldo.
He said while it was a "huge disappointment, when we step away I think we can be quite proud of the performance today".
"We know how to adapt to different opponents".
During Mexico's testy 2-1 victory, undercover Federation Internationale de Football Association agents in plain clothes were scattered throughout the stands.
The victory came at a cost, with Borussia Dortmund defender Raphael Guerreiro helped off on 65 minutes with a suspected broken leg.
Things remain tight in Group A before Saturday's final round.
The referee had to separate the two sides as Mexico defeated New Zealand 2-1 in Sochi.
This was Ronaldo's seventy-fourth goal for his country.
"We knew it was going to be a hard game against a very strong team".
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The New Zealand forward had the best of the early chances when he twice forced Mexico goalkeeper Alfredo Talavera into saves. Twelve months on from his European Championship success, Ronaldo plainly has his eyes on the right to call himself one of the world's team of continental champions.
Ronaldo was on target in the eighth minute to silence the 42,759-strong crowd at Moscow's Spartak Stadium, and was named man-of-the-match as after their first game against Mexico.
Herculez Gomez and the FC panel look at Mexico's lacklustre win over New Zealand and the changes that affected their play.
"It's many, many millions who every time Cristiano plays are very interested in watching him play", Santos said.
However, he was all smiles, escorting a young mascot in a wheelchair onto the Moscow pitch before netting his first Confederations Cup goal.
"It's nothing much, just heat of the moment stuff", said Wood when asked for his take on the incident.
"If we play like we did the other night, I have all the confidence in the world".
Portugal earlier beat Russian Federation one-nil in Moscow. Coach Juan Carlos Osorio says it will be the flawless opportunity to show that Mexican soccer has matured and reached a level at which it can succeed under the most hard circumstances. New Zealand's Captain, Chris Wood slotted the ball into the net after he got the ball when he ran into space.
Osorio said the All Whites should have stopped playing at that point so the injury could be assessed.
Mexico ended the day as Group A leaders with four points, ahead of Portugal on goal difference.
Russian Federation coach Stanislav Cherchesov said he will decide his starting line-up after training with an electric atmosphere expected for the national team's first game at the Kazan Arena.
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