The 33-year-old received his marching orders for an alleged tug on defender Jeison Murrillo's hair at the Mestalla just 27 minutes into his Champions League debut for Juventus.
UEFA will now open disciplinary proceedings with a decision over his ban set for September 27, and Ronaldo could face up to a three-game ban.
Berbatov, who played alongside Ronaldo for one season at Manchester United, has explained why his reaction was valid.
"I couldn't believe the red card that Cristiano Ronaldo was given against Valencia," he told Betfair.
"It was a ridiculous decision. You could see he was thinking 'what the f are you doing ref?' in his reaction as he went off.
"Some people might think crying is an overreaction but sometimes when you are lost in the moment, your passion takes over.
"It was his first game for his new team in the Champions League and he will be have been desperate to perform.
"Meanwhile, just another hat-trick for Lionel Messi. These two are like Ali v Frazier - they keep pushing each other to greater heights, driving each other on. It's great to watch. Let's hope they continue!"