With the Canadiens losing 2-1 at the start of the third period, Domi -- acquired from Arizona in the offseason -- began tugging on Ekblad's shirt, asking him to fight. With the Florida star showing no interest to drop the gloves, Domi punched him in the face twice with two lefts, but still Ekblad didn't respond.
That's when Domi dropped his right glove and sucker punched him in the nose. The bloodied Ekblad dropped to the ice, left the game -- at the NHL's request -- and did not return. Domi was given a minor, major and match penalty.
Ekblad went through tests after the game and cleared concussion protocol.
"We definitely won't forget about it," Panthers goalie Roberto Luongo said. "You don't do that. You respect your opponents, and if your opponent doesn't want to engage in a fight, there's no reason to drop your glove and punch him square in the face. Bit of a gutless play. You don't do those types of things."
The NHL announced Domi's discipline Thursday after a hearing on Wednesday's incident.
The Associated Press contributed to this report.