Cleveland Browns defensive end Myles Garrett admitted he "lost his cool" after starting the brawl which marred their 21-7 victory over AFC North rivals Pittsburgh Steelers on Thursday evening.
Cleveland's scrappy win at the FirstEnergy Stadium was overshadowed by an ugly skirmish between Garrett and Steelers quarterback Mason Rudolph with eight seconds remaining in the match.
Garrett and Rudolph wrestled on the ground well after the quarterback had passed to Trey Edmunds for an 11-yard gain.
The Cleveland player then ripped off Rudolph's helmet and swung it at the Pittsburgh man, making contact with his head.
The Steelers' offensive linemen David DeCastro and Maurkice Pouncey then tackled Garrett to the ground, with Pouncey punching and kicking the defensive end in the head before the Browns' defensive tackle Larry Ogunjobi ran in and pushed Rudolph to the floor.
Garrett, Pouncey and Ogunjobi were all ejected from the game, with the Browns defensive end expected to be given a lengthy ban by the NFL.
Speaking to NFL.com, Garrett said: "I made a mistake, I lost my cool and I regret it. It's going to come back to hurt our team. I appreciate my team having my back but it should've never gotten to that point. It's on me.
"A win's a win. I don't think it was overshadowed by what happens in eight seconds. What we did on the opening 59 minutes should not go unnoticed.
"It was embarrassing. What I did was foolish and I shouldn't allow myself to slip like that. It was out of character, but it was a situation like that, it is an emotional game, and I allowed myself to follow through those emotions.
"I've hurt the whole team with what I did and could come back to hurt us. I don't know what sort of repercussions I will face but it's got to be better."
Rudolph tried to defer from answering questions surrounding the incident in his post-match press conference but did describe Garrett's actions as "cowardly".
He said: "I thought it was pretty cowardly. I got sacked, we exchanged some words, he kept keeping on and one thing led to another.
"You can go back and watch the tape if you want and make your own assumptions."
Cleveland quarterback Baker Mayfield, who is good friends with Rudolph, could not defend his team-mate's actions.
"It's inexcusable," Mayfield told FOX Sport. "I don't care, rivalry or not, you can't do that. That's kind of the history of what's been going on here lately, hurting yourself.
"It's inexcusable. Garrett knows that. I hope he does now. It's tough."
Steelers head coach Mike Tomlin declined to comment on the incident, while opposite number Freddie Kitchens said he was "embarrassed" of his defensive end.