Montreal, which has lost its past four, got goals from Arber Xhekaj and Josh Anderson.
Sam Montembeault, claimed off waivers by Montreal from Florida in 2021, took the loss after making 34 saves.
Barkov got the fourth hat trick of his career with three goals scored in vastly different ways.
The first, 2:37 into the game, came when Gustav Forsling’s shot hit Barkov’s skate and went past Montembeault.
Barkov, playing in his first game after missing the past three with a lower-body injury, got his second on a snapshot from the left circle while the third was scored in front of the net off a loose puck.
“He changes every part of your game,” Florida coach Paul Maurice said of having Barkov back.
Florida led 3-2 going into the second after Anderson scored his ninth of the season on an extended power play with 46.1 seconds remaining in the first.
Tkachuk gave Florida some breathing room with the team’s second power play goal of the game by deflecting a long shot from Brandon Montour at 6:22 of the second.
“I thought we were ready to be good early in the game,’’ Maurice said, “and I think we gave up six even-strength shots in the final two periods. We got to be pretty good there, playing with the lead.’’
Verhaeghe’s team-leading 18th goal came on a breakaway at 4:14 of the third. Tkachuk made it 6-2 at 7:24 of the third with the team’s third power play goal of the night.
“Barkov coming back from injury, he obviously had a very good first period,’’ Montreal coach Martin St. Louis said. “That kind of carried them through the game. Those are repetitions you cannot buy. They learned from that.”
NOTES: Barkov recorded his hat trick within the opening 15:22 making it the fastest three-goal game in franchise history. His second goal came on the power play, giving him 67 in his Florida career making him the franchise leader. Barkov had been tied with Scott Mellanby, who started with the team during its expansion season in 1993 and was the team’s second captain. Barkov already owned the franchise record for goals scored, now with 229. … Florida not only got Barkov back from injury, but defenseman Radko Gudas also returned to the lineup after missing 10 games with a concussion. … Linesman Ryan Jackson appeared to sustain a knee injury when he was taken down during a scrum between Florida’s Marc Staal and Montreal’s Joel Edmundson midway through the third. Florida athletic trainer Dave DiNapoli attended to Jackson on the ice. Jackson was helped off the ice by Staal and DiNapoli and taken to the Florida medical room.
Canadiens: At Washington on Saturday night.
Panthers: At Carolina on Friday night.
George Richards, The Associated Press