CLEVELAND — The Browns kept fighting long after the outcome had been decided, and it likely will cost them their best defensive player.

And maybe their season.

Browns defensive end Myles Garrett ripped off quarterback Mason Rudolph’s helmet and hit him in the head with it in the final seconds as the Browns’ 21-7 win over the Steelers on Thursday night ended with a wild brawl between the rivals.

Garrett faces a likely suspension for his actions, and Steelers center Maurkice Pouncey will likely be disciplined for kicking Garrett in the head.

“I lost my cool and I regret it,” Garrett said. “It’s going to come back to hurt our team. The guys who jumped into the scrum, I appreciate my team having my back, but it never should have gotten to that point. It’s on me.”

Players from both sidelines spilled onto the field during the melee, which began after Garrett wrestled Rudolph to the ground well after he completed a short pass on a meaningless play. Garrett, Pouncey and Browns defensive tackle Larry Ogunjobi were ejected.

Rudolph got his hand on Garrett’s helmet first as the players grappled on the ground, but Garrett escalated the brawl after he got back on his feet. He yanked the helmet off Rudolph and swung wildly, hitting the quarterback on the top of the head.

Rudolph threw his arms in the air in disbelief after the impact, and Pouncey retaliated by punching and kicking Garrett.

“I thought it was pretty cowardly and bush-league,” Rudolph said. “I’m not going to back down from any bully. I felt like I had a bone to pick with him. I appreciate the line always having my back, but I was angry.”

Browns quarterback Baker Mayfield called Garrett’s actions “inexcusable” and Fox commentator Troy Aikman said they were “barbaric.”

Mayfield said the incident overshadowed a win that the Browns should be celebrating.

“It feels like we lost,” he said.

Browns receiver Odell Beckham Jr. was shown replays of the brawl on the NFL Network set.

“It’s ugly,” Beckham said. “It’s not something we want in the NFL.”

Rudolph, a second-year player who took over for the injured Ben Roethlisberger in Week 2, has already missed time this season with a concussion after he was knocked unconscious from a helmet-to-helmet hit by Ravens safety Earl Thomas.

“Myles is very upset about it. He’s got to maintain his composure,” Browns coach Freddie Kitchens said.

Before the ugly ending, Mayfield threw two touchdown passes and scored on a 1-yard plunge as Cleveland held on to defeat the banged-up Steelers for just the fourth time in 10 years and improved to 2-0 in the AFC North for the first time.

The Browns (4-6) have won two in a row after dropping four straight, a skid that put first-year coach Freddie Kitchens’ job in jeopardy.

But Mayfield’s 8-yard TD pass to undrafted rookie tight end Stephen Carlson with 5:25 left helped clinch a rare win over the rival Steelers. And a softer upcoming schedule has eased the pressure on Kitchens and given the Browns some hope they can end the NFL’s longest playoff drought.

The loss was especially damaging to the Steelers (5-5).

Pittsburgh lost its top two playmakers as running back James Conner (shoulder) and wide receiver JuJu Smith-Schuster (concussion) suffered injuries in the second quarter and didn’t return.

Without them, Rudolph didn’t have enough help and threw four interceptions.