PITTSBURGH — Standing at his locker a few minutes after the Penguins saw their six-game winning streak conclude after a surprising loss against one of the NHL’s worst teams, Sidney Crosby contorted his body to show what little contact he made with Calgary Flames goaltender Devin Cooley in the game’s deciding moment.

Officials Francois St. Laurent and Alex Lepkowski didn’t see it that way.

Tommy Novak’s tying goal in the third period was waved off by the officiating crew, and the Penguins, in one of their more underwhelming performances of the season, fell to the Flames 2-1 at PPG Paints Arena on Saturday.

They next play 24 hours later in Boston.

Crosby wasn’t pleased with the ruling.

“I think it looks bad,” Crosby said. “But being in the play, I felt like I did my best to try and avoid the goalie. I got pushed into him.”

The goal was immediately ruled off, and the Penguins did not challenge the play.

Had they challenged the play and lost the challenge, they’d have been short-handed for two minutes, hardly ideal when already trailing with less than 10 minutes remaining in the third period.

Dan Muse said he wasn’t confident that the Penguins would have won the challenge and didn’t think it was worth the risk.

Crosby was pretty adamant that the goal should have counted.

“The explanation (I was given) had something to do with being in the crease,” he said. “But you’re allowed to be in the crease as long as you don’t impede the goalie. I was trying to get through there and got pushed back.”

Crosby believes the goaltender, Cooley, embellished the play.

“He did a good job of selling it,” the Penguins’ captain said. “I grazed him. He went down pretty easy. What are you going to do? It’s a hard one to challenge. It doesn’t look great. But just being part of the play, I know I was going to get around (Cooley) if I didn’t get pushed into him.”

Connor Zary gave the Flames the lead early in the first period.

Egor Chinakhov evened the score in the second period by blasting an Evgeni Malkin pass past Cooley.

However, Matt Coronato scored early in the third period for the Flames during a lull in play from the Penguins. Calgary was able to hold off the Penguins for the remainder of the afternoon.

“You’re not going to have good starts all the time,” Crosby said. “Games are going to have momentum flows. Unfortunately, we weren’t able to build off that second-period momentum.”

Goaltender Artūrs Šilovs stopped 23 of 25 shots for the Penguins, who lost for the first time since Dec. 23.

 Ten postgame observations 

• I can see exactly where Crosby is coming from, but there is a bigger issue here, and it’s one we’ve discussed many times over the years. What exactly is goaltender interference? I ask this honestly.

Nobody really knows. It says what it says in the rulebook, but if NHL officials followed what the rulebook says, each team would have 10 power plays per game.

It’s a massive problem for the NHL, and, as I’ve said many times, it’s going to cost a team a championship one of these years. Perhaps then the NHL will be a little bit more urgent about making things more precise.

Was it goaltender interference? Crosby went through the crease, so I don’t think he was shocked by the ruling, and it’s a risk when that happens. But I do agree with him that Cooley went down quite easily.

Crosby was quite upset about it following the game. Even after his interview, I chatted with him about it for a minute, and he spoke with pretty strong conviction about his belief that it was, indeed, not the correct call.

• My guess is that it wouldn’t have been overturned had the Penguins challenged. This isn’t to say that it shouldn’t have been.

But we all know the drill by now. On plays such as that, the play isn’t going to get overturned often, regardless of the ruling.

Crosby was of the opinion that it should have been ruled a goal and then Calgary should have been given the right to challenge. It probably would have stood in this case. The initial call is typically honored.

• The Penguins played a very, very poor hockey game.

Much like on Thursday night against New Jersey, they were especially poor in the first period.

They allowed a breakaway and a two-on-one in the first three minutes. That’s not a good way to go about winning.

Ryan Shea has been one of the most reliable Penguins this season, but his turnover led to Calgary’s first goal.

The Penguins need to eliminate the bad starts. Quickly.

• The Penguins were horribly cavalier with the puck most of the game, and especially in the first period.

Erik Karlsson and Kris Letang were the biggest offenders. Letang has been playing better lately, and Karlsson has been outstanding most of the season, but neither was the least bit crisp in this game.

They have the puck so frequently that the Penguins can’t survive when they’re sloppy simultaneously.

Letang, by the way, fanned on a puck, which trapped him and led to Calgary’s winning goal on a three-on-two.

It wasn’t a strong game for anyone on the blue line other than Brett Kulak, who I thought enjoyed one of his better games as a member of the Penguins.

• Regardless of everything mentioned above, this was a terrible game to lose. Yes, the Penguins had won six in a row, so it’s not the end of the world. But when you’re in a dogfight to make the postseason, losing at home to the Flames is never going to be a good look.

The Penguins looked good for most of the second period and made a late surge, but still, this performance wasn’t nearly good enough.

• Really nice performance from Silovs.

The goals he allowed were on odd-man rushes, and he had many of those to contend with.

His athleticism was on display, and he kept the Penguins in the game during a poor third period. It was a solid effort.

• It was an interesting day for Chinakhov.

He absorbed an enormous hit from Brayden Pachal in the second period. It was clean, but it was vicious.

A couple of shifts later, Chinakhov delivered a bang of his own.

The guy can shoot the puck. He’s a very intriguing talent.

• Following that goal, Malkin was given a roughing penalty for crushing Zary behind the net.

It wasn’t the smartest play in the world, but I found it kind of amusing. A classic Malkin moment if ever there’s been one.

• Bryan Rust didn’t play and is day to day with a lower-body injury.

As a result, Kevin Hayes entered the lineup and centered Justin Brazeau and Anthony Mantha. That line did not play very well.

Crosby played with Rickard Rakell and Novak.

Rust’s importance to the Penguins goes without saying.

• Even though the Penguins won the previous six games, I didn’t like this performance at all. Far too cavalier. Far too sloppy. Far too much east-west and cuteness with the puck.