OTTAWA — Question the Pittsburgh Penguins’ ability to stay healthy. Question their defensive work. Question some of their decision-making. For that matter, question their ability to reach the postseason. It’s all perfectly fair.

But under no circumstances should their heart be questioned. Not after this season and certainly not after this game.

Sidney Crosby left with an injury early in the second period at Canadian Tire Centre on Thursday night, but the Penguins, mired in a funk and playing in a building that has never been kind to them, willed their way to a victory. Erik Karlsson and Rickard Rakell led the way as the Penguins won 4-3 in a shootout.

“Not bad,” Karlsson said with a smirk. “We fought for this one.”

That they did.

Crosby appeared to have his legs pinned against the boards on a hit from Nick Cousins late in the first period. The Penguins captain left the game immediately. He returned for the second period but left after one shift.

He was seen after the game walking around the dressing room without a noticeable limp. Coach Dan Muse confirmed it was a lower-body injury that knocked Crosby from the game but didn’t have any other information.

The Penguins started playing better with Crosby out of the lineup. Karlsson, in the midst of a brilliant stretch, explained.

“I think it’s everybody (stepping up),” Karlsson said. “When Sid leaves the game, we have two options. We can hang our heads and admit defeat. Or you can say, ‘I’m going to do my absolute best with him out.’ I think we did that today. Not just myself. Everybody chipped in.”

Karlsson scored one goal and set up two Rakell lasers for the Penguins offense. Rakell scored his second goal in the third period to put the Penguins ahead 3-2 on a power-play goal. Drake Batherson’s second goal of the game evened it for Ottawa two minutes later.

The Penguins, who dominated the second period, hung on for dear life for the remainder of the third. Once the point was secured, a dramatic overtime ensued, with Stuart Skinner and Linus Ullmark making a series of sensational saves. Egor Chinakhov and Ben Kindel scored in the shootout to give the Penguins a much-needed 2 points.

“I think that second period, we just played our game and took over,” Ryan Shea said.

Up next for the Penguins is a Saturday matinee at home against the Dallas Stars.

“Everybody wants to get in (the playoffs),” Rakell said. “And, I mean, we want it so bad. So we’ve got to do everything we can to win hockey games.”

Ten postgame observations

• There aren’t many details about Crosby right now. Hopefully, we will know more by tomorrow.

He seemed in reasonably good spirits after the game. He spoke briefly with Muse outside of the dressing room and chatted with other staff members before walking to the team bus. He was dressed in a suit and tie and didn’t appear to have a brace or any kind of support on his leg or knee.

This can mean nothing, of course. The bad news is he immediately left after his first shift in the second period, so he knew something was wrong, and he wasn’t able to play through something. The good news is it doesn’t appear anything catastrophic happened.

• There is something truly admirable about this team. The Penguins were already playing without Evgeni Malkin and have been horrible defensively in recent weeks. They fell behind 1-0 and 2-1 in a building where they’ve won only seven times in regulation during the 21-year Crosby era.

And they just keep fighting.

Bryan Rust and Kris Letang also left momentarily with injuries. This is a bruised and battered team, and one dealing with the pressure of a remarkably deep Eastern Conference field breathing down its neck. Still, every time you think they’re going to blink, they roar back. Other than the 2017 Stanley Cup team that willed its way to a championship on fumes and without Letang, this is the most resilient team I’ve covered in my 17 years on the Penguins beat.

• You know the rotation Muse has used with his goaltenders almost all season? Well, I’d start Skinner again Saturday against Dallas.

No, he’s not perfect. And I didn’t love the Batherson goal in the third period. But Skinner earned himself another start with the way he performed in the remainder of the third period, overtime and the shootout. Artūrs Šilovs has not played well in recent games — and frankly, neither has Skinner.

However, Skinner showed up in a big, big way. Dallas will be quite a test Saturday, but Skinner knows the Stars well, and this performance should be rewarded. He stopped two breakaways in overtime and gave the Penguins their best goaltending performance in quite some time.

Stuart Skinner makes a leg pad save with Ottawa's Ridly Grieg and Pittsburgh's Sam Girard jostling in the corner of the crease.

Stuart Skinner locked in during the third period and overtime to help secure 2 points. (Marc DesRosiers / Imagn Images)

• I’ve run out of superlatives for Karlsson. Right now, he’s the best defenseman in the league.

He’s played all 14 games in March, and in those contests, he’s produced eight goals and 21 points. That’s an absurd total for a defenseman. Or for any player, for that matter.

When Crosby left, Karlsson literally took over during the second period. It was a mesmerizing performance. He deserves to be in the Norris discussion given the season and the March he’s having. Brilliant, brilliant stuff.

(And, as he reminded me while leaving the dressing room, this was his first goal ever against his old team. He was quite amused by this.)

• The second period might have been the Penguins’ best of the season. Muse was thrilled with it, as were his players.

After allowing the second Ottawa goal, the Penguins clamped down and did everything right. That should be the template for how this team needs to play, with or without Crosby and Malkin. Their cycle game was excellent, their blue line executed breakouts well, and they simply outworked the Senators.

• I loved how Shea and Connor Clifton performed in this game. They were exactly what a good third pairing should be: strong in front of the net, physical and making good decisions all game.

• As for the second pairing, I can see why the Penguins want to keep Letang and Sam Girard together. It’s not that they necessarily like how that pairing looks, but they like their first and third pairings when Letang and Girard are the second pairing.

I didn’t like how Girard played the game’s first goal when Batherson scored on the power play; he was out of position on the play. However, Girard did get stronger as the game elapsed. Letang played a nasty, physical game and did some good things. He was just unacceptably bad in the second period when the rest of his team was outstanding.

His decision to hold the blue line led to Nick Cousins’ goal early in the second period, and he did precisely the same thing later in the period, which almost led to another goal. Sometimes, as a defenseman, you have to retreat. For some reason, he wouldn’t do it on those two rushes and made a couple of other horrible decisions with the puck. He simply has to know better.

• Kindel’s poise is something. Yes, he ended the game with the shootout winner, but I’m not even talking about that. When he touches the puck, the Penguins calm down. Every time.

He’s 18.

• It wasn’t a great night for everyone. Tommy Novak is really off his game right now. So is Justin Brazeau. Ville Koivunen isn’t helping his cause. I didn’t think Elmer Söderblom was so good, either.

I’m going to start beating the Rutger McGroarty drum on a regular basis. He can help this team right now, and it’s curious that he hasn’t been recalled.

• Muse is 0-for-9 on goalie interference challenges, a truly marvelous feat. The Penguins killed off the Ottawa power play after a challenge on the Batherson goal in the third period.

That wasn’t a great challenge. There wasn’t much chance of that one being overturned even though there did appear to be minor contact with Skinner in the crease.

But I’m not here to rip Muse. Far from it. Every time I’m about to doubt this team’s chances of making the playoffs, they roar back. Though the Penguins could use a dose of good news on the health front, there’s not much question they hired the correct coach last summer.

A remarkable season rolls on.