A fight broke out at the end of the Chiefs’ win over the Lions after Detroit defensive back Brian Branch slapped Kansas City receiver JuJu Smith-Schuster.

The brawl occurred just after Chiefs quarterback Patrick Mahomes kneeled down to run out the rest of the clock and the players started to shake hands.

Branch walked right by Isiah Pacheco and snubbed a handshake from Mahomes before getting into the face of Smith-Schuster and slapping the Kansas City receiver.

Pacheco tried to keep Branch back after the punch, but Smith-Schuster came racing back toward him and tried to take some revenge — which set off a massive melee.

Watch the fiery scenes in the video player above

The situation quickly got under control as cool heads prevailed.

Following the loss, Branch explained the blow came out of frustration after he was blocked in the back illegally by Smith-Schuster at the end of the game in front of officials.

“They trying to bully me out there,” he said, while also adding he “shouldn’t have did it” in regards to the skirmish.

“It was childish,” Branch said.

Lions head coach Dan Campbell wasn’t happy with his star player and did not hold back when discussing the incident following the contest.

“I love Brian Branch, but what he did is inexcusable and it’s not going to be accepted here,” he said.

“It’s not what we do. It’s not what we’re about and I apologise to coach (Andy) Reid and the Chiefs and (Smith-Schuster). That’s not OK. That’s not what we do here and it’s not going to be OK. He knows it, our team knows it and so, that’s not what we do.”

There’s no question that Branch will be getting a call from the league over the incident, though it’s unclear who else will be getting reprimanded for the postgame fight.

“I mean, we play the game in between the whistles,” Mahomes told the NBC broadcast. “They can do all the extra-curricular stuff they want to do.”

Branch does have a history with the league, as he was ejected last year during a game against the Packers after delivering a late hit on receiver Bo Melton.

He then flipped off the crowd and was called for an unsportsmanlike conduct penalty.

Branch later apologised for his actions.

Frustration was evident for the Lions on Monday (AEDT) as they fell 30-17 to the Chiefs.

This article originally appeared on the NY Post and was reproduced with permission.