The Pittsburgh Penguins not only lost Game 4 to the Tampa Bay Lightning, they lost one of their most important defensemen. They lost their composure. And their backup-turned-starting goalie, through little fault of his own, may have lost his net.

The night got off to a bad start for Pittsburgh when Tampa’s Ryan Callahan scored on the opening shift, just 27 seconds in. By the end of the second period, the Bolts had built a 4-0 lead.

“It’s hard to chase a four-goal deficit,” said head coach Mike Sullivan. “We were not the more determined team for the first half of the game. They’re a good team. We knew this was going to be a hard game; we knew they were going to push. But I don’t think we played the way we’ve been playing that has allowed us the results we’ve gotten here over the postseason.”

One way the Penguins were markedly different was in allowing themselves to grow frustrated with Tampa’s physical game and retaliate to perceived missed calls. That gave the Lightning opportunities to go to work on the power play and generate momentum.

“You just take a punch,” said Kris Letang, whose double-minor midway through the second helped the Tampa Bay power play extend a what felt like a surmountable, 2-0 lead to a backbreaking, 3-0 one. “The best thing for me is to just walk away; skate away. That’s it.”

“We’d like him to handle it differently,” Sullivan said. “He’s too important to our team, and that’s what I told him. Every team we play against goes after him. For the most part, he’s had great composure in playing the game the right way. But we would like him to respond differently to that circumstance – and he will, moving forward.”

Shortly before Letang’s penalties, things had escalated with a big hit by Callahan sending defenseman Trevor Daley awkwardly into the boards. Daley, so important to the Penguins’ ability to move the puck and start the offense from the back end, couldn’t get up without assistance, and left the arena on crutches and in a left-foot boot.

“It’s big because he’s a huge player for us,” Letang said. “Plays a lot of minutes; has a lot of speed. Plays the power play and the PK. A great leader in our room. It’s a huge spot to fill, but it’s the playoffs; somebody has to rise to the occasion if he’s not playing.”

With the way the game was going, although most of the four goals weren’t rookie netminder Matt Murray’s fault, Sullivan decided to change things up for the third period. Usual No. 1 netminder Marc-Andre Fleury came in for his first game action since sustaining a concussion March 31, and looked sharp in the seven stops he had to make.

“I thought he looked good,” Sullivan said. “We were down four goals; sometimes, when you make a change like that, it has an impact on your team. I thought the goals we gave up were good goals on their part; Matt made some big saves in there. But sometimes, when you make that decision, it can have an influence on your team moving forward. And it gave Marc a chance to get into some game action.”

Fleury’s teammates decided to change things up, too – or, more accurately, to show up. The Penguins brought speed, energy and offense to match nearly the entirety of their first two periods to a 16-shot third. And the goals started to come.

Red-hot Phil Kessel scored just 1:18 into the period. And, when slumping Evgeni Malkin and Chris Kunitz found the net in a two-minute span midway through frame third to pull within a goal, it began to look like the Penguins just might pull off the impossible and come all the way back.

They didn’t.

“I don’t think we deserved it,” said captain Sidney Crosby. “I think we all feel that way. We can’t expect to play like that in the first half and get the results we want. We didn’t have the desperation we needed early on until we were down four goals, then we found it.”

But the near-comeback sends the Penguins, now in a deadlocked, 2-2 series, back to Pittsburgh for Sunday’s Game 5 on a significantly higher note than the blowout this game was shaping up to be.

“We just have to understand that’s how we need to play,” Crosby said. “That level of desperation in every game regardless of the score of the series, or what happened the game before. This one’s over and done with now. We had a good third and, hopefully, we can build off of that.”

“We’ve got to make sure we keep the focus and just continue to play the right way,” Sullivan said. “We take each game as it comes and we prepare the same way, with the same focus, determination and conviction.

“We played a team tonight that was ready to play; they played extremely hard. I trust our guys. They know what they’re up against, and they know what the response needs to be from our side.”

Who will be in goal?

“I haven’t even really given it any thought at this point,” Sullivan said.

Both goalies have made their cases – Murray with his play each time he’s been called upon this year, and Fleury with a third period that proved he was ready to get back into game action, not to mention a body of work that includes a Stanley Cup.

“My job doesn’t change; I just have to be ready if my name’s called,” said Murray. “It was just a weird game. From getting clocked behind my net by my own D-man [Brian Dumoulin], to goals going off their shin pads, weird bounces all over the place. I can’t control most of that. I thought I was in position most of the time.

“Their last two goals were just brutal bounces; good bounces for them. But I felt really good. I competed really hard. I did everything really well, I thought.”

“I was a little nervous; it’s been a while since I played. Excited, too,” Fleury said. “They’re big games, intense games, so it’s fun to be part of.”

It will be a lot more fun for the Penguins if the third-period version of their team shows up.

“They outcompeted us in the first two periods; they just wanted it more than we did,” Murray said. “You see the ups and downs of the game there. We know if we play the way we did in the third period, we’ll be all right.”