Ronaldo was shown a red card by German referee Felix Brych in the 29th minute at Estadio Mestalla after an altercation with Valencia defender Jeison Murillo.
The decision seemed harsh. Ronaldo was being tracked by Murillo in the penalty box and aimed a small kick at his opponent as they tussled.
Murillo instantly fell to the ground and, after consulting his assistant on the goalline, Brych sent Ronaldo off.