The Pittsburgh Penguins’ 4-1 defeat at the hands of the Dallas Stars at PPG Paints Arena on Tuesday was unsightly for a variety of reasons.

• It was their third consecutive loss.

• They yielded a lead they earned after a strong first period.

• Their power play once again was blanked, going 0 for 4, including a four-on-three sequence that lasted 39 seconds.

But the ugliest portion of the setback was witnessing rookie defenseman John Ludvig suffer a suspected head injury in a frightening fashion during his NHL debut.

At 10:41 of the second period, Ludvig, a stout defender who isn’t leery of physical play, initiated contact and slammed violently into Stars forward Radek Faksa in the neutral zone. In the process, Ludvig’s face struck Faksa’s helmet and both players fell to the ice.

While Faksa sprung to his skates almost immediately, Ludvig remained prone for several minutes. Play was halted as Penguins athletic trainer Chris Stewart and Dr. Dharmesh Vyas as well as Stars medical staffers attended to Ludvig.

Eventually, the sturdy 6-foot-1 and 213-pound Ludvig was able to recover to his skates but was so wobbly that he required assistance from Penguins forward Noel Acciari and defenseman Marcus Pettersson to reach the rampway to the dressing room.

The team did not formally identify the nature of Ludvig’s injury, but it’s fair to assume he suffered a head injury of some type as evidenced by his bloody mouth. Penguins coach Mike Sullivan did not provide a substantive update on Ludvig and simply indicated he was still being evaluated. According to goaltender Alex Nedeljkovic, Ludvig was walking and speaking with team staffers within the Penguins’ facilities at the arena following the contest.

“It was scary,” Penguins forward Lars Eller said. “I felt terrible for him. I hope he’s OK under the circumstances. I’ve seen that a couple of times and it (stinks) every time. It’s a scary moment. Hopefully, he’ll be OK.”

It might be a stretch to suggest the Penguins are OK considering they are mired in a season-worst three-game losing skid.

But they seemed to display some improvement Tuesday from Saturday’s apparently unappetizing 4-2 road loss to the St. Louis Blues.

At least by their own auditing.

“We were better because we certainly were horrible (Saturday) night,” forward Bryan Rust said. “We were better, but we weren’t good enough. There’s obviously still areas that we need to clean up. Offensively, we should try to get a few more bodies to the net and try and to score some ugly goals.”

Rust scored his team’s only goal on a somewhat pretty sequence 19:22 into regulation.

Driving the play through the neutral zone, Stars forward Roope Hintz lost possession thanks to 6-foot-5 Penguins defenseman Ryan Graves, who used his pool skimmer of a stick to strike the puck away. As Hintz tried to regain possession, Penguins defenseman Kris Letang poke-checked the puck away at the blue line, allowing Penguins forward Sidney Crosby to claim it and bank a pass off the near boards.

Getting behind Stars defenseman Jani Hakanpaa, Penguins forward Jake Guentzel generated a two-on-one rush with Rust. As Stars defenseman Thomas Harley slid down to take away the pass, Guentzel was able to slip the puck past Harley’s skates into the top of the crease where Rust tapped in a forehand shot over goaltender Jake Oettinger’s glove for his fifth goal of the season. Guentzel and Crosby had assists.

A crucial juncture of this contest occurred at 6:16 of the second period when Eller, in a short-handed sequence, raced into the Stars’ zone on the right wing and ripped a wrister over Oettinger’s glove, only to clap it off the crossbar.

The next shift, the visitors tied the game 1-1 at 7:37 of the second period via forward Jason Robertson’s first goal.

After Penguins defenseman Ryan Shea lost the puck battle in his own left corner to Hintz, Stars forward Craig Smith fed a pass from the end boards to the left circle for Robertson, who swiped a one-timer on net. Nedeljkovic made the initial save with his left leg but allowed a considerable rebound. Robertson corralled the loose puck in the slot and managed to tuck a backhander under Nedeljkovic’s left leg while falling. Smith and Hintz tallied assists.

“We (could) go up 2-0 (being) short-handed,” Eller said of his non-goal. “Instead, they (make it) 1-1 the next shift. Sometimes, those go your way and sometimes, they don’t. Today, they just didn’t. We go up 2-0 there, I like to think we can find a way to get those two points. Sometimes, that’s the difference. You get the crossbar and out or crossbar and in. Sometimes, it’s a game of inches.

“That right there was a matter of inches.”

Following Ludvig’s departure, the Stars took their first lead at 16:03 of the second period with forward Evgenii Dadonov’s first goal.

Off a give-and-go sequence with Stars forward Tyler Seguin, Harley moved his way up the left wing wall of the offensive zone and snapped a wrister toward the cage. Planted in front of Nedeljkovic, forward Matt Duchene was stuck by the puck but managed to fend off Letang then settle the rebound and flick a backhander to the front of the crease where Dadonov out-muscled Penguins forward Rickard Rakell and jammed in a forehand shot by Nedeljkovic’s left skate. Assists went to Duchene and Harley.

A comedy of errors by the Penguins led to the Stars’ third goal at 5:22 into the third period by Harley.

After Crosby lost a puck in front of his own bench, Robertson poke-checked it past Graves in the Penguins’ high slot. Nedeljkovic made an ill-conceived lunge from his crease to stab the puck away. As Nedeljkovic clumsily attempted to return to the net, Stars forward Joe Pavelski collected the puck on the left half wall and fed it to the slot for Harley, who could have used a rake to fire his wrister into the open cage for his first goal. Pavelski and Robertson registered assists.

Nedeljkovic didn’t shy away from accepting responsibility for his faux pas.

“It was a split-second decision,” said Nedeljkovic, who made his second start of the season. “It was the wrong decision. I’ve got to just let whatever happens, happens and play it out.

“Tonight, overall we did a great job of putting pucks behind them and being disciplined in that aspect. I’ve got to do the same thing and make some better decisions than I did tonight.”

The Stars delivered the coup de grace at 13:51 of the third when forward Wyatt Johnston was credited with his second goal on a frantic goalmouth scramble that was verified by a brief video review.

Taking a pass low to the left of the cage, Johnston spun this right and lifted a backhander that clunked off the near post. The puck struck off Nedeljkovic’s derriere then came to a rest against the near post. As Nedeljkovic reached back to smother the puck with his glove, Johnston persisted and jabbed at the puck, causing it to cross the goal line. Forward Jamie Benn had the lone assist.

Three of the Stars’ goals involved a person in a white jersey barging into the blue paint allegedly under protection by someone in a black jersey.

The Penguins suggested something of an allegory in of how the victors generated their offense.

“We needed to just try to get some dirtier ones,” Rust said. “We need to get a few more bodies to the net, try and get some rebound chances, try to get some screens. We had a little bit of it, but I don’t think we had enough.”

There wasn’t enough on the power play either, though the Penguins did manage to record a robust 10 shots with the man advantage.

“We’ve just got to simplify a little bit,” said Rust, recently promoted to the top power-play unit. “Shooting more pucks, try to get some ugly goals. There’s been a lot of good passing plays without any results. When things don’t go your way, you’ve got to simplify.”

Simply put, Tuesday’s loss was ugly for a variety of reasons. But it wasn’t completely lacking cosmetically.

“That’s the tough part is there was a lot of good in that game,” said Nedeljkovic, whose record fell to 1-1-0 after he made 31 saves on 35 shots. “A lot of good.

“Unfortunately, there (were) some questionable decisions on my part that ended up costing us. We’ve got to find a way to move on, take the positives. We’ve got another game in two days (at home against the Colorado Avalanche). Find a way to flush this one and get ready for Thursday.”

Notes:

• Rust has needed six games to reach five goals this season. He needed 18 games to reach that barrier last season.

• Forward Matt Nieto was the Penguins’ lone non-goaltender who failed to record a shot in this game.

• Ludvig became the 19th player in franchise history to wear No. 7 in a game of consequence. His predecessors:

Art Stratton, Lou Angotti, Bryan Hextall, Steve Durbano, Russ Anderson, Rick MacLeish, Ian Turnbull, Rod Buskas, Joe Mullen, Andrew Ference, Kelly Buchberger, Matt Hussey, Michel Ouellet, Mark Eaton, Paul Martin, Matt Cullen, Colton Sceviour, Dmitry Kulikov

• Penguins defensemen P.O Joseph and Chad Ruhwedel were healthy scratches.