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 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.
- Bolts deal McDonagh to Preds, agent calls client's departure 'crushing'
- Boeser opens up about last season's struggles, eager to bounce back
- Jackets GM: Laine's contract status won't affect draft weekend plans
- Jets officially name Rick Bowness head coach
- Report: Flyers prospect detained for planning to evade military service