Ruiz insisted Steven N'Zonzi should have been sent off for hitting out after the pair clashed, with referee Lee Probert only issuing a yellow card.
Ruiz said: "I thought it was boxing. It was a punch, I felt it and that is what Damien Duff said it was.
"I said to the referee he has a very heavy hand if he just pushed me. I felt a punch, close to me ear."