[9] Halak had signed with the team during the off-season,[10] and approaching the trade deadline the Bruins acquired forwards Charlie Coyle and Marcus Johansson.

While the Blues were able to advance past their fellow expansion franchises, each Finals appearance ended with them being swept by Original Six teams that comprised the East Division, concluding with their 1970 defeat.

[22] In game one, Brayden Schenn scored the first goal of the Finals for the Blues, firing a wrist shot past Tuukka Rask.

In the second period, Bruins forward David Pastrnak mistakenly passed back to an open Schenn who gave the puck to Vladimir Tarasenko who doubled the lead for St. Louis.

The Bruins quickly scored after, as a pass by Sean Kuraly deflected off of intended target Connor Clifton's skate and then goalie Jordan Binnington's stick and into the net.

In the third period, Boston gained the lead as a net-mouth scramble ended up on Sean Kuraly's stick who fired it past Binnington.

The Blues struck back when Robert Bortuzzo's shot deflected off of Matt Grzelcyk and squeaked past Tuukka Rask on the short side.

The Bruins scored 40 seconds later to take the lead again with Joakim Nordstrom moving around the St. Louis defenceman and backhanding his shot past Binnington.

During the overtime period, Bruins defenceman Brandon Carlo tripped up Alexander Steen and on the delayed penalty, Carl Gunnarsson fired a slap shot past Rask giving St. Louis their first victory in the Finals in franchise history and tying the series 1–1.

With power-play given to the Bruins from the failed offside challenge, David Pastrnak capitalized in the second period, backhanding his shot past Binnington.

However, the Bruins quickly had their four-goal restored when Colton Parayko was sent to the penalty box for high-sticking and Torey Krug cashed in for Boston's third power-play goal of the game.

In the third period, a roughing penalty by Bruins captain Zdeno Chara proved costly as Parayko scored on the given power-play, his slap shot deflecting off of Brandon Carlo.

Boston added another power-play goal with Marcus Johansson's slap shot cleanly beating Allen finalizing the score at 7–2.

The Bruins counter-attacked when Zdeno Chara shot at Jordan Binnington and the rebound went to Charlie Coyle who slid it past the Blues goaltender.

In the second period, with Boston forward Connor Clifton resigned to the penalty box for an illegal check to the head, the Bruins, shorthanded, tied the game as Brandon Carlo picked up a rebound to shoot it past Binnington.

In the third period, controversy occurred when Blues forward Tyler Bozak tripped Noel Acciari, but no penalty was called on the play.

The Bruins got on the board with less than seven minutes remaining when Oskar Sundqvist high-sticked Torey Krug, causing a delayed penalty, and the Boston defenceman passed to an open Jake DeBrusk who fired it past Binnington.

In the third period, Bruins defenceman Brandon Carlo shot a bouncing puck towards Jordan Binnington which snuck under the Blues goaltender's blocker for the second goal of the game.

The Bruins regained their three-goal lead when the Blues in a defensive scramble left David Pastnak alone in front of the net and he fired the puck past Binnington.

[28] In game seven, Jay Bouwmeester's shot got through a screen of players and Ryan O'Reilly tipped the puck past Tuukka Rask for the opening goal.

The Blues increased their lead with eight seconds remaining in the first period when Jaden Schwartz passed to an open Alex Pietrangelo who backhanded his shot for his third goal of the playoffs.