He had no idea he was about to play the biggest game of his life.
He received 9:36 of ice time, but Beaulieu accomplished a lot in that short time to help the Canadiens win 4-0 and force a Game 7 on Wednesday (7 p.m. ET; NBCSN, CBC, RDS) at TD Garden.
Beaulieu joined the Canadiens during the first round of the Stanley Cup Playoffs as one of the "Black Aces." Three weeks later, he found himself helping Montreal stave off elimination.
"When you come here as a 'Black Ace', you've got to stay ready. You have to come here with expectations that anything can happen," Beaulieu said. "The best way to put it is I was overwhelmed, very happy with the opportunity.
"I just tried to take full advantage of it."
Lars Eller opened the scoring at 2:11 of the first period on Beaulieu's first shift of the game, snapping a streak of 149:38 without scoring an even-strength goal against Bruins goalie Tuukka Rask. Beaulieu didn't play a big role on the goal, which came off a Kevan Miller giveaway to Eller right in front of the Boston net, but it still allowed him to settle into the game right off the bat.
Beaulieu was inserted into the lineup by Therrien because of his offensive skills, and he showed them with an instinctive play to set up the biggest goal of the game.
With the Canadiens clinging to a 1-0 lead in the second period despite carrying much of the play to that point, Beaulieu grabbed a loose puck off a blocked shot by defense partner Mike Weaver. This was his first playoff game as a professional hockey player, his first game of any kind since April 19, and Beaulieu made a play that a seasoned veteran might not have considered.
When Beaulieu looked up he saw forward Max Pacioretty racing up ice, so he lofted a pass into the neutral zone, hoping it would somehow bounce to his teammate.
That's exactly what happened when Loui Eriksson missed catching the puck before it bounced past Dougie Hamilton and into the Boston zone. Pacioretty beat Zdeno Chara to the loose puck and poked a shot through Rask's legs at 15:24 to give the Canadiens a 2-0 lead.
It was the breathing room the Canadiens needed, and they never looked back.
One might call that pass to Pacioretty a lucky bounce, but it never would have happened if Beaulieu hadn't attempted it.