A confidence rattler? 3 takeaways from Chicago Blackhawks’ 6-loss.

If Saturday’s matchup against the Boston Bruins was a litmus test for how the Chicago Blackhawks stack up to the league’s upper echelon, then it’s back to the lab after the 6-1 drubbing.

The Hawks have been outmatched before, but the gap looked even larger than the five-goal margin would indicate.

“They have high-level skill and compete, and what happens is we start chasing them around and we get out of our zone structure,” coach Luke Richardson said. “They do that, seams open up, and that’s when things start going.”

The Bruins dominated the puck in the first period, which led to an 11-1 advantage in high-danger chances (five-on-five) in the second, according to naturalstattrick.com.

In the final minute, the Hawks were scrambling to play spoiler as they kept Patrice Bergeron from reaching his 1,000th-career point after a goal and assist put him at 999. Bergeron had three cracks at it.

And why not? The Hawks were handing out shots on goal — 43-18 — like a promotional giveaway.

That kind of shot disparity is an eye-opener, especially when each team had three power plays: David Pastrňák and Jake DeBrusk hit the mark on two for the Bruins, and Jonathan Toews scored the lone goal for the Hawks, his’ eighth of the season.

Boston’s second-ranked penalty kill allowed just six goals on 64 opportunities coming into the matchup. On the flip side, the Hawks coughed up goals on two of three kills after shutting down the last 11 chances over the previous four games.

The Hawks have allowed at least five goals in back-to-back games after losing 5-2 to the St. Louis Blues Wednesday.

The Bruins put on an exhibition on how to keep a defense on its heels.

They attacked so many different ways, throwing a barrage of bodies and pucks at Mrázek until Pastrňák poked in the opening goal on the power play. They were content to buzz around the perimeter until David Krejci got loose for a one-timer. And they seamlessly zipped passes to each other on a breakout, freeing up Nick Foligno to deke Jason Dickinson between the legs and feed Pastrňák on a two-on-one.

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“I don’t think we played it with enough confidence,” defenseman Connor Murphy said. “We let them kind of dictate plays and cycle around our zone, and we weren’t staying close and together defending. They thrive on turnovers, whether it’s around our blue lines or in the neutral zone. And we did that too often.”

“They just have a lot of movement,” Richardson said of the Bruins. “I think what happens is you get mesmerized. (If) we don’t kill a play right away, which is the key, (then) it doesn’t matter what kind of system you try to do. And if you don’t, you’re going to be in trouble. We weren’t strong on killing plays early.”

Mrázek had 37 saves for the Blackhawks.

Richardson said, “We really didn’t help him by (not) holding our structure in front of him. Made it very difficult. For a goalie to go side to side, it’s very exhausting.”

Overshadowed by all this, defenseman Ian Mitchell made his season debut after recovering from a wrist injury. He played about 16 1/2 minutes, including some on the power play and penalty kill, and took no shots.

Here are three takeaways from the loss.

They admittedly looked “sloppy” against the Blues, but they looked beaten — like, downtrodden — by the Bruins.

If there was one thing you could count on, even in a loss, is that the Hawks will be scrappy. That’s not a slight, just an acknowledgment that while they can’t always generate a wealth of chances, they can fall back on a solid, patient defensive structure and wait for their opportunities to strike. But they’ve been looking a lot more “scrambly” since the 3-0 loss to Carolina.

Connor Murphy said, “I don’t think anyone’s lacking a lot of confidence. But I think when goals start going in maybe guys are not making as (many) confident plays.”

Richardson was asked if players are doubting themselves.

“It always happens when the game’s not going well. People get grumpy and they bang their sticks or slam doors. And that frustration sets in,” he said. “And what it does is, it clouds your mind for keeping it clear for what you need to do.”

He added, “We have to have a little more accountability … through work ethic and (leading) by example.”

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Maybe the Hawks’ only mental issue is fundamentals.

“We turned the puck over way too much,” defenseman Jarred Tinordi said. “We knew what kind of team they were. Credit to them, they play fast and they capitalize on those chances.

“But we didn’t take care of the puck enough tonight. And it hurt us.”

On the first power play, the Hawks couldn’t muster a shot on goal but they gave up two shorthanded attempts.

On the second man-advantage, the Hawks changed things up.

Defenseman Filip Roos was replaced by a fifth forward, Philipp Kurashev. After the swap, the Hawks got on the board with Toews’ tip-in goal.

Kurashev was credited with a secondary assist, but it started with Patrick Kane’s seam pass to Kurashev, who centered to Max Domi at the point. Domi launched a shot, and Toews chopped it past Bruins goalie Jeremy Swayman.

Richardson was pleased with how the forwards rotated at the top of the formation with Toews expertly playing the middle and Taylor Raddysh working down low.

“He’s obviously great at that,” Richardson said of Toews, “getting pucks out and taking sticks on pucks.”

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The Hawks had to try something with Seth Jones still sidelined with a thumb injury. Caleb Jones was scratched Saturday, but he hasn’t moved the needle on the power play the previous five games.

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From this one-game sample size, the five-forward group didn’t look vulnerable defensively, like they were at risk of giving up a shorthanded chance. However, on the second unit, Richardson said, “we’re definitely going to have one or two D out there.”

Toews’ goal in the second period was his eighth this season and fourth on the power play. His on pace for what would be a career-high 39 goals.

He also had another strong night at the dot, winning 60% of his faceoffs. And even that pales to his 78% against the St. Louis Blues. He leads the league at 65%.

Earlier this season, Toews was “not even” close to calling this a bounce-back year until he got his all-around game to his liking. The former Selke winner was on the ice for three of Boston’s six goals Saturday.

But Richardson likes what he’s seen so far.

“He’s driven, like, if he loses that one draw, he’s analyzing it,” he said before the game. “He makes adjustments. He’s a big, physical, strong guy with good stick skills. And he’s got experience. He’s well versed on who’s going to go up against every night.”