ST. LOUIS — The NHL trade deadline, as we should all know by now, is a crapshoot. A dozen or teams may feel like they won the day but, come June, there really is only one winner.

Last year, the Bruins surely felt like they hit a home run when they acquired Rick Nash and, for a few short weeks, it looked like that was the case. But when a high hit gave Nash the last concussion of a career that ended too soon, all the B’s had to show for it was a quick second-round exit and a squandered first-round pick.

This year, the response to GM Don Sweeney’s moves from a lot of observers was pretty tepid by comparison. But those two moves are a huge reason why the Bruins are where they are, just wins away from the Stanley Cup.

Some people who were in love with Ryan Donato’s skill level hated to see him go (along with a fourth-rounder) to Minnesota for fellow local boy Charlie Coyle.

And the acquisition of Marcus Johansson for a second-rounder this year and fourth next year was pretty much met with a collective “meh.” But not anymore, especially after each notched a goal and an assist in the B’s 7-2 rout of the St. Louis Blues in Saturday’s Game 3 of the Stanley Cup Final.

“Listen, trade deadlines, and I’m sure GMs will tell you the same thing, it’s probably not the route you want to go every year,” said coach Bruce Cassidy. “It’s just so hard to win and there’s one winner left and that’s usually how they judge you. If you win it’s a good deal and if not.... But at the end of the day, those guys have been great for us and good for Donnie. He made the right moves. You always have to give up something and we’ll see how it turns out with Ryan Donato. The draft picks you never know. They’ll pick their guys. But so far it’s worked out well for us. Charlie has really solidified us and JoJo’s been a wild card.”

The two newcomers have combined with Danton Heinen to create a third line that has been nothing short of a godsend for the Bruins.

Coyle, after some struggles to produce in the regular season, is fifth on the team in playoff scoring with 8-7-15 totals while Johansson has 4-7-11 totals.

Coyle, who unlike Johansson has a year left on his deal, was slow to percolate as he bounced between right wing and center but he’s blossomed since his role as third line center has become more defined. Coyle takes a lot of pride in being versatile, but he also believes the old saying “jack of all trades, master of none” can manifest itself.

“When you do that, I think it can take away from your consistency a little bit. You can be good at this position and that position, but it’s like doing two different things in life. If you focus on too many things, you can’t be great at them,” said Coyle. “Once I got that under my belt and I got planted at center and got familiar linemates every night, you gain chemistry. And I’m playing with great players, too. That helps.”

The chemistry between Coyle and Johansson was evident on Saturday when they combined for the B’s second goal that sent them on their way. Johansson sold the shot to just about everyone in the building — except Coyle.

“It doesn’t look like the passing lane is there. I’m thinking he’s going to shoot the puck and got to the net, but at the last second I thought, ‘Well, it’s JoJo, this could be on your stick.’ Then all of a sudden, boom, it’s right on your tape and there’s a lot of net to shoot at because of how he fakes it,” said Coyle.

Shortly after he arrived, Johansson missed three weeks with a lung contusion and then missed a couple of games in the Toronto series with an unspecified injury. Cassidy is just now appreciating all that Johansson can bring, including a blistering shot like the one he scored on in garbage time on Saturday, as well as some David Krejci-like subtleties to his game.

“When you’d see Washington, you’re always looking at Backstrom and Ovechkin, Oshie and Wilson,” said Cassidy, admitting he didn’t have a full appreciation of Johanson when he first arrived. “But now you’ve learned that, though he’s a deceptive skater like Krech, he can really separate and get into open ice. And he is like Krech in that he slows the game down, he’s looking for late plays. But I’ve also seen him attack a little more in the playoffs, deciding that if the play’s not there, I’m going to the net. A little greasier game, and this time of year, that’s required. With his injuries when he first got here, you didn’t know if that’s going to come out.”

But it’s all coming out now for both Johansson and Coyle. And this time around, Sweeney was able to hang on to his first-round draft pick. No matter how the rest of this series goes, the GM did a bang-up job at the deadline.