PITTSBURGH — Alex Bump hadn’t played an NHL game in 13 days. Inserted into the Philadelphia Flyers’ lineup in place of a healthy Matvei Michkov, though, Bump made an impact right away Monday night against the Pittsburgh Penguins. The 22-year-old rookie, playing on a line with Noah Cates and Tyson Foerster, scored a second-period goal with a power move to the net in his playoff debut and finished with a team-high four shots and nine shot attempts.

If only the rest of his teammates showed the same kind of jam.

The Flyers lost Game 5, 3-2, at PPG Paints Arena, failing to close out their first-round series wth Pittsburgh for the second time after initially ripping off three straight wins. They’ll get another chance Wednesday in Philadelphia, and to avoid a return trip to Pittsburgh for a Game 7 on Saturday, they simply need more contributions from up and down their lineup.

“A couple guys … they look a little sluggish,” coach Rick Tocchet said after the game, which was similar to his message after Game 4. “The pace, it’s all brand new to them. … I think it’s important we understand that there’s another pace.”

At this point, it’s impossible to predict whether this young team will find it against a Penguins team that is steamrolling ahead, even if Monday’s game-winning goal by Kris Letang was a bit fluky, as a rebound off the glass behind goalie Dan Vladar somehow squeaked through his legs.

Too many Flyers haven’t been noticeable for the past two games. It may be the weight of the moment finally getting to them.

“We knew it wasn’t going to be easy,” Travis Sanheim said when asked about the pressure ramping up. “You look at the guys on that (Penguins) roster, and they’re not going to go down without a fight. (It’s) just sticking with our game plan. … There’s still chunks of these games we’ve been losing that we’ve controlled play and been able to establish the way that we want to play. Just take that and just apply more of it, and the results will come with that.”

Other than Bump and Denver Barkey, both named by Tocchet as players who had strong efforts in Game 5, the Flyers seem to be wilting as the series moves along.

Porter Martone had just one shot in Game 5 and looks to be hitting a wall. Owen Tippett also had just one shot and has been quiet for the past two games after being such a consistent force for weeks. Foerster is still scoreless in the series, and Emil Andrae, inserted back into the lineup after missing the last three games, took a blatant tripping minor at 1:37 of the third period with the Flyers trailing 3-2. Perhaps Michkov will get a chance to return for Game 6, but he obviously hasn’t done anything of note yet, either, or he wouldn’t have come out in the first place.

The Penguins are unlikely to let their collective foot off the gas, particularly with the prospect of becoming the first team in 12 years, and the fifth in NHL history, to complete a reverse sweep. If there was pressure on the Flyers in Games 4 and 5, it will be ratcheted up to monumental levels to not end up on the wrong side of a Game 7 in Pittsburgh.

Step one in getting their game back for Game 6 is to handle the Penguins’ forecheck a lot better than they did Monday. It led directly to the Penguins’ first two goals.

Anthony Mantha won a battle with Rasmus Ristolainen before finding Elmer Soderblom in the slot for a goal just 2:45 into the game. Early in the second, Tippett’s clearing attempt was intercepted by Sidney Crosby. The Penguins captain then spotted a wide-open Connor Dewar, who blew a shot by Vladar to make it a 2-0 lead at 3:17 of the middle frame.

“Obviously, they’re coming hard, but there are some more battles that we have to win that we were winning earlier in this series,” Sanheim said. “And executing our wall play — just hasn’t been enough of it the last two games.”

Perhaps the biggest disappointment from a Flyers perspective is that, Soderblom’s goal aside, they were the much better team through the first 10 minutes of the first period. Tocchet spoke before the game about how, earlier in the series, the Flyers were putting their “foot in the water (to) see the temperature. We want to dive in.”

They did, headfirst, in Game 5, with dangerous chances in tight by Bump, Barkey and Tippett. But they couldn’t maintain that early burst of energy, and even when they did have the puck in the offensive zone throughout the game, it was a struggle to get it on net. The Flyers finished with 20 shots on goal but missed the net 22 times and had 16 attempts blocked.

And to the surprise of no one, the power play again came up small, going 0-for-2 with just one shot. The Flyers had a chance to tie it after Barkey drew a trip on Sam Girard shortly after Soderblom’s goal. They set up and enjoyed some zone time, but the only puck that got through was a 60-foot wrist shot from the point by Cam York, who was only on the ice because the penalty was about to expire.

In the last minute of the first period, still down 1-0, Trevor Zegras lost the handle on a breakaway opportunity, and his between-the-legs attempt moments later from just off the side of the post went high and wide. Zegras, too, had his worst game of the series.

“We need to hit the net more on tight chances — and grade-A chances,” Tippett said. “We had a lot of chances that either didn’t hit the net or there was a guy in the lane. I think for the most part we can do a better job hitting the net.”

There’s a word for that this time of year: desperation, which the Flyers need to start ramping up. According to Sanheim, it hasn’t been at a high enough level when compared to Pittsburgh.

“Not as much as them, obviously,” Sanheim said. “So we’ve got to regroup, get ready for the next one and find that desperation. Because I think going home in our building, we’re still in a good spot. We’ll need a big effort.”

They’ll also need Vladar to come up with his best game of the series.

Though the game-winning goal was indeed strange, Vladar had a chance to glove the floating puck from Letang from high in the Penguins’ zone. He missed it, then couldn’t find it when it sailed behind him and ended up in his skates. Bad luck, yes, but Vladar, who finished with 18 saves on 21 Penguins shots, can’t be totally absolved of it.

Asked about the late second-period Letang goal that came just two minutes and six seconds after Sanheim had tied the score with a shot off Erik Karlsson’s stick, Vladar said, “It’s an unfortunate bounce, to be honest with you. You can always do something better on every single goal — doesn’t matter if it’s a bounce off the boards or a 2-on-0 breakaway. You can always do something a little bit better. (The Penguins) just got that bounce that we didn’t.”

Goaltending was supposed to be the Flyers’ biggest advantage in the series. But Vladar has made a pair of regrettable mistakes in the past two games, and he isn’t outplaying Arturs Silovs, who has now stopped 45 of 50 Flyers shots in back-to-back wins after replacing Stuart Skinner.

The Flyers will have to make it tougher on Silovs in Game 6 and force him to make more saves. That will only happen if they do it as a team.

“Some guys (have) got to loosen up a bit,” Tocchet said. “We’ve got to get some other guys to hold on to pucks and win some battles in the corners. That’s what it comes down to. That’s playoff hockey.”