A brawl unfolded in the stands on Sunday evening in Kanata, Ont., during a game between the Ottawa Senators and the Toronto Maple Leafs.

From a cellphone video circulating on YouTube, it’s unclear what the argument was about.

What is clear is that a beer got dumped by a man in a Leafs jersey onto a man in Senator’s red, and two men went tumbling dangerously through the stands.

The video starts with a male wearing a Toronto Maple Leafs jersey getting an earful from a blonde-haired woman in a Senators’ jersey in a row in front of him.

After she sits down, a man in Senators’ red continues the argument with the fan in the blue Leafs jersey.

Someone yells, “Give him the Todd Bertuzzi,” after which the fan in red reaches out -- possibly trying to shove the Leafs fan. (Todd Bertuzzi is notorious for a brutal on-ice hit against Steve Moore.)

From behind, someone in Leafs’ blue pours a beer right over the head of the Senators fan. The punches start to fly and the Leafs’ fan jumps at the Senator’s fan, tackling him and causing them both to fall down the aisle.

It’s not clear who won the fight, but the Leafs ended up winning the game 5-3.

It was the first time Ontario’s two NHL teams sparred this season. Their first game was postponed on Oct. 22 following the shooting of Cpl. Nathan Cirllio.