Watch: Cooper ejected after tirade directed at referee
Cooper was heated at the share of penalties after a scrum broke out toward the end of the second period.
The Lightning went down two men after the skirmish. Both Corey Perry (double-minor) and Anthony Cirelli were booked for roughing, and the team was given a bench penalty.
Bryan Rust and Mark Friedman were both handed roughing infractions for Pittsburgh.
The Lightning ultimately killed the penalties to kick off the third period, but Pittsburgh took home a decisive 5-1 victory.
Cooper said he was shocked about the ejection and wasn't given an explanation, according to The Athletic's Joe Smith.
"I'm not so sure in all the years, what I said is something he'd never heard before in the history of reffing," he said.
The coach added: "That team, for some reason, they're by far the lowest penalized team in the league. I'm not sure why, but they are."
Cooper has been the subject of the two most recent coaching ejections in the NHL. He was also given the heave-ho in a March 2020 contest with the Boston Bruins.
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