Blackhawks’ offense suffocated, Adam Boqvist concussed as Blues sweep season series

The Blackhawks showed plenty of emotion but practically no execution on a big stage Sunday.

Hosting the defending Stanley Cup champion and archrival Blues on a national broadcast called and produced — for the first time — by an all-female team on International Women’s Day, the Hawks were shut out 2-0 by backup goalie Jake Allen.

In two home games this season against the Blues, the Hawks went scoreless. They were 0-4 against them overall this season.

‘‘It’s important games for us [against a] divisional rival and a team we’re trying to catch up to, as far as how they play and their habits,’’ coach Jeremy Colliton said. ‘‘There’s a reason why they’re leading the division. On the whole, we haven’t been good enough over the four games.’’

The crowd of 21,815 — the third-largest this season at the United Center — spent most of its energy fending off loud chants from thousands of invading Blues fans.

Their only moment to cheer came when a hit by the Blues’ Oskar Sundqvist on the Hawks’ Adam Boqvist in the second period sparked a line brawl, highlighted by Drake Caggiula — alarmingly, given his lengthy concussion history — exchanging haymakers with Vince Dunn.

And that moment might have been the worst of the game for the Hawks, considering it left them without Caggiula (hand injury) and Boqvist (concussion protocol) the rest of the way.

With their short bench, the Hawks didn’t muster a shot on goal in the first 12 minutes of the third period. By that point, they trailed by two goals and seemed dead and buried.

‘‘It’s a team we don’t like very much to play against,’’ defenseman Connor Murphy said. ‘‘[When] things escalate like that, you want to be able to rub it in as much as you can by getting a win. . . . We didn’t do that, and that definitely hurts.’’

The Sundqvist-Boqvist incident dominated much of the postgame discussion.

Originally called a major penalty after Sundqvist missed his initial hit but followed through into Boqvist’s face with a flailing arm, the penalty was downgraded to a two-minute minor upon review.

The rules differentiating major and minor penalties in that circumstance are gray, but the Hawks thought the collision deserved a major, especially because Boqvist skated off immediately with a bloody face and later entered the concussion protocol.

‘‘There was no reason for the contact to his head,’’ Colliton said. ‘‘It was totally unrelated to the play. It was late. He was trying to get him, so he did.

‘‘We end up losing an important player for us for the rest of the game. . . . And we end up with a two-minute power play. Doesn’t seem on the right level, if you ask me.’’

The Hawks’ power play, of course, still had a chance to tie the score with the two-minute man advantage but predictably failed. The unit went 0-for-4 with only one shot on goal and has converted only 12.6 percent of its chances since Dec. 14.

Meanwhile, the Hawks’ playoff hopes are on life support after two winless games Friday and Sunday against the NHL’s worst (Red Wings) and best teams (Blues).

That reality finally seemed to seep into the locker-room mood after the loss.

‘‘We have to find ways to win each game differently,’’ Murphy said. ‘‘And we’re not doing a good-enough job of that when things seem to get tighter as the end of the year comes.’’