The Madrid centre-back was shown a straight red card in the 77th minute following a reckless two-footed tackle on Lionel Messi.
Ramos responded angrily to his dismissal and was seen gesturing at Pique as he left the pitch, with the crowd at the Santiago Bernabeu not pleased with referee Alejandro Hernandez's decision either.
However, Pique is adamant there cannot be any discussion over whether Ramos deserved to walk, with Barcelona eventually recording a hard-fought 3-2 victory against 10 men, Messi netting a 92nd-minute winner.
"I am convinced that he will realise it was a clear red card once he gets home and sees it again," Pique was quoted as saying by AS.
"He went into the tackle with both feet forward when Messi got away. It was all very clear, he goes in there with his studs up and does not get the ball. There is no discussion about it.
"What happened is that the people here are used to that referees allow a lot of things and then when that does not happen...
"I saw Ramos pointing at me after the red card, but he will regret what happened when he sees the incident again. It was a very clear red card."