Ryan Babel has conceded his actions were "stupid" when receiving a red card against Benfica, but the Liverpool forward believes referee Jonas Eriksson treated him harshly.
Babel was dismissed after 30 minutes for raising his hands to defender Luisao and Liverpool subsequently squandered a 1-0 lead to lose 2-1 at Estadio da Luz in the first leg of their Europa League quarter-final.
And while Babel believes his behaviour did not warrant a dismissal, he has accepted culpability for the incident and pledged to avoid similar behaviour in future.
"The referee told me the red card was for touching Luisao's face - that was it," Babel said. "It was clear that Luisao had made an awful foul and all I wanted to do was back up Fernando.
"Too harsh maybe. In the end maybe it was a stupid, silly thing for me to touch him in the face, but I think a yellow card would have been fair enough. But if they are the rules...
"He came very loud and very close with his face and I just tried to back him off with my hand (to say) don't come too close. That's it and in the end, they made it bigger than it was. But it was a mistake by me, I will learn from it and it won't happen again."