The Bruins have not played many stress-free hockey games this season. More often than not they are locked in a one-goal game when the third period rolls around.

But on Thursday, the B’s enjoyed what was a rarity for them — a relatively anxiety-free 5-2 win over the St. Louis Blues at the Garden. Though the score was lopsided, it wasn’t an easy game for Joonas Korpisalo, who turned aside 37 shots for his first since Nov. 6.

The B’s broke open the game with a three-goal second period and cruised to the victory behind Pavel Zacha’s two goals. The B’s never trailed.

After playing catch-up – and failing – in Detroit in Tuesday, the Bruins this time got the early jump on their opponent, taking a 2-0 first-period lead on a pair of goals from their erstwhile first line.

The first one was a nice play off the rush at 6:30. Elias Lindholm made a nice backhand pass to Morgan Geekie to give him the puck with speed going down the left wing. As a quick 2-on-1 developed with Alex Steeves, Geekie made a slick adjustment to his forehand and made the pass over Steeves for his sixth of the year.

Geekie doubled the lead at 11:25, thanks to some good work by Steeves, who beat two Blues behind the net to get the puck to Elias Lindholm low in the right circle. The centerman found an open Geekie in the slot and his shot broke off Jordan Binnington’s arm and in for Geekie’s 21st of the year.

The only penalty of the period went to Tanner Jeannot, a phantom hooking penalty, but it was the B’s who had the best scoring chance after Steeves stole the puck in the St. Louis zone but could not beat Binnington.

While the B’s held a 14-10 shot advantage, they were a little sloppy in their own zone and Korpisalo had to be sharp. He was, building off a good third period in Detroit after he relieved Jeremy Swayman.

But the Blues kept coming in the second period and halved the lead at 1:59. Big defenseman Colton Parayko carried the puck down low and behind the net before feeding Pavel Buchnevich for the one-timer goal from the left circle.

That gave the Blues some legitimate signs of life. They started causing the B’s major problems in breaking the puck out of their zone.

But on one such occasion, Mason Lohrei took a feed from call-up Victor Soderstrom behind the net and mushed it all the way out himself. He gained the offensive zone and fired a low percentage shot from the left wing. Binnington directed it to the right boards, off which Viktor Arvidsson stepped into a slapper that beat the goalie over the shoulder for Arvidsson’s seventh at 6:04.

The B’s then grabbed firmer control of the game at 12:26. Zacha first won a puck in the defensive zone to get it over to Lohrei, who in turn dished it to Arvidsson. Arvidsson first whiffed on his first pass attempt then connected with Zacha on his second. Zacha cut to the high slot and sizzled a wrist shot over Binnington’s glove arm. It was Zacha’s first goal in 10 games.

But he wasn’t done.

Jake Neighbors took the Blues’ first penalty of the game with 15 seconds left in the period. That was enough time – just enough – for the B’s to extend the lead to 5-1. With time running down, Elias Lindholm shoved a loose puck to Zacha on the right side and he buried his seventh of the season with 0.1 second left in the period.

The Blues actually held a 15-8 shot advantage in the second period, but they were in a deep, deep hole.

The Blues did get back on the board in the third period at 9:07. A second after Korpisalo made a great pad save on Dylan Holloway, the netminder did not have enough time to reset before Pius Suter roofed a shot from the top of the crease.

That is as close as they got.