Players from the New York Rangers and Washington Capitals threw their gloves to the ice and started throwing punches as soon as the puck was dropped in their matchup in New York on Thursday.
Rangers players sought revenge after the Caps' Tom Wilson beat and injured a star player in their last meeting several days ago.
Three separate fights broke out in the opening seconds and others, including one involving Wilson moments after he stepped on the ice, occurred early in the first period in a return to the NHL's "old school" days when brawls were more common and more vicious.
The bad blood between the teams stems from Tuesday's game, where the towering Wilson tossed around New York Rangers' Artemi Panarin, an NHL most valuable player candidate.
Panarin will miss the final three games of the season due to an injury sustained in the fight.
Just prior to taking down Panarin, Wilson had punched Rangers' Pavel Buchnevich in the back of the head while he lay prone on the ice.
Wilson, a repeat offender who has been suspended five times for violent acts, was fined just US$5,000 for his actions and was not suspended.
That decision led the Rangers to issue an unusually strong statement that described what occurred as a "horrifying act of violence" while calling for the removal of George Parros, the NHL head of player safety in charge of handing out punishment, for "dereliction of duty."
The prospect of bloodshed had hockey and non-hockey fans alike glued to the game.
"Say what you will about fighting in hockey. This is the first time this year that I tuned in for the Washington Capitals. I'm sure I'm not alone," said retired player Marc Methot said on Twitter.
"That 1st period start was awesome."
Another former player PJ Stock, who played for the Rangers for three seasons, delighted in the decidedly gladiatorial spectacle.
"So...everyone hating the #nyr #caps game so far? Turning it off?" said Stock. "Deep down as much as you hate it or disagree with it - you can't stop watching it. Damn you entertainment!!"