Ronaldo was shown a second yellow card for what Bengoetxea deemed to be a dive inside the penalty area.
He had booked the Portugal captain moments earlier, after he ripped off his shirt when he made it 2-1 with a stunning drive.
After he was shown the red card, the 32-year-old momentarily lost his cool and shoved the referee.
Bengoetxea included the altercation in his post-game match report, writing: “Player: Cristiano Ronaldo Dos Santos Aveiro. Once the red card was shown, the player pushed me slightly in a sign of disagreement.”
The shove could trigger a ban of up to 12 matches under Article 96 of the Spanish federation’s rule book, which deals with “Slight violence towards referees”.
Article 96 applies to players who “grab, push or shake” a referee in a manner that is “slightly violent”, and recommends a suspension of 4-12 matches for the action.
Ronaldo’s fate is now in the hands of the Spanish federation’s competition committee, who will decide how many games he would be banned for, in addition to the one-game ban from his red card.