Ronaldo and Juventus are currently in pre-season friendly action against Tottenham as the Old Lady look for a winning start under Sarri.
The Italian was named as the club’s replacement for Massimiliano Allegri last month after the 51-year-old chose to take a sabattical.
Juventus and Tottenham are currently drawing 2-2, with Ronaldo and Gonzalo Higuain scoring for Juve and Erik Lamela and Lucas Moura on target for Spurs.
But Ronaldo appeared to react angrily after Sarri decided to take him off with the match still up for grabs.
The Portugal international was hooked by his manager and replaced by Matheus Pereira.
But he had a tense exchange of words with his boss on the touchline.
Ronaldo and Sarri initally clasped hands where the 34-year-old leaned his head in, looking none too pleased to be making way.
Former Chelsea boss Sarri then responded by shrugging before camera footage pans away from the duo.
Ronaldo is somebody hungry to win every game and never likes being substituted given his unbelievable appetite to win.