At some point in the near future, the Pittsburgh Penguins are going to have to adapt to the blunt reality of life without superstar forwards Sidney Crosby and Evgeni Malkin.

Especially because each of them is almost 40 years of age.

On Saturday, they got a refresher of how difficult that existence can be during a 6-3 loss to the Dallas Stars at PPG Paints Arena.

Crosby was scratched because of an undisclosed injury he suffered during a 4-3 road shootout win against the Ottawa Senators on Thursday, and Malkin was sidelined for a third consecutive game with an unspecified ailment.

The Penguins’ penalty killers continued to struggle as the Stars scored a pair of power-play goals. It marked the fourth consecutive game in which the opposition scored a power-play goal against the Penguins’ penalty kill, which has been ranked at the top of the NHL for much of the season.

Offensively, the Penguins didn’t fare much better as they were limited to 12 shots, one more than the franchise record for fewest shots in a game.

Goaltender Stuart Skinner, getting a rare second consecutive start, unofficially made 20 saves on 24 shots as his record tumbled to 21-15-9.

Penguins forward Anthony Mantha opened the scoring 132 seconds into regulation during a power-play sequence with his 27th goal of the season.

Off some passing around the perimeter of the offensive zone, Penguins defenseman Erik Karlsson accepted a puck at the left point, maneuvered forward a bit and pumped a wrister toward the cage. Anthony Mantha planted his 6-foot-5 and 240-pound frame above the crease and deflected the puck downwards through goaltender Jake Oettinger’s legs. Karlsson and forward Rickard Rakell had assists.

Stars rookie forward Justin Hryckowian tied the score with his 12th goal 2:10 into the second period.

Accepting a pass in the left circle of the offensive zone, Stars forward Colin Blackwell deked past a poke check attempt by Penguins defenseman Connor Clifton and surged to the slot, only to lose control of the puck. Hryckowian, stationed just below the left circle, located the puck out of a mass of bodies and swept a forehand shot past the left skate of Penguins rookie forward Ben Kindel as well as the glove of a sprawling Skinner. Assists belonged to Blackwell and linemate Jamie Benn.

Karlsson responded 48 seconds later with his 13th goal.

Alertly keeping a puck onside at the left point of Dallas’ zone, Penguins defenseman Parker Wotherspoon immediately centered it to his defensive partner, Karlsson. Settling the puck, Karlsson coasted in a bit, loaded up, then gripped and ripped a wrister over Oettinger’s glove. The lone assist went to Wotherspoon.

Stars forward Jason Robertson scored his 40th goal during a power play at 7:12 of the second frame.

Off a short-area pass from Stars forward Mikko Rantanen in the high slot, Robertson backtracked a bit then lobbed a wrister by Skinner’s glove. Stars forward Wyatt Johnson supplied an effective screen on the sequence. Rantanen and forward Matt Duchene were deemed worthy of assists.

The Stars took their first lead exactly three minutes later when Rantanen found his 21st goal during another power-play opportunity.

Settling a puck in the Penguins’ right circle, Robertson circled back to the near point and snapped a pass to the lower right circle, where Rantanen leaned on his left knee and ripped a one-timer to the near side that clunked off Skinner’s left arm and deflected into the cage. Robertson and defenseman Miro Heiskanen harvested assists.

Stars defenseman Lian Bichsel got in on the act with his fourth goal at 11:38 of the second.

After Bichsel appeared to grab his stick near the Penguins’ left circle, Karlsson let go it, allowing it to tumble to the ice. As Karlsson turned his attention to referee Michael Markovic to protest, Stars forward Mavrik Bourque settled a puck in the left corner, then slid a pass to the high slot where Bichsel pumped a one-timer past Skinner’s glove. Mantha appeared to screen Skinner inadvertently during the sequence. Members of the Penguins directed further protests to Markovic to little avail. Bourque and forward Oskar Back bagged assists.

The Penguins called a timeout to get reorganized after that score.

Karlsson had a hand in more offense at 8:54 of the third period when forward Noel Acciari scored his 10th goal.

Off some furious work to keep a puck onside at Dallas’ blue line and to create some space, Karlsson fed a pass from the center point to the right half-wall where Penguins forward Elmer Soderblom cranked a one-timer. Acciari, battling in the crease with Stars defenseman Tyler Myers, allowed the puck to strike off the shaft of his stick and deflect past Oettinger’s right shoulder. Penguins forward Connor Dewar screened Oettinger on the sequence. Soderblom and Karlsson collected assists.

Any notion of a comeback was snuffed out when Bourque scored his 15th goal on an empty net at 16:52 of the final frame. Myers had the only assist.

Bourque scored again on an open cage at the 18:48 mark off an assist by Benn.

Notes:

• The Penguins recalled rookie forward Rutger McGroarty from Wilkes-Barre/Scranton of the American Hockey League prior to the game. In corresponding transactions, forwards Avery Hayes and Joona Koppanen were assigned to Wilkes-Barre/Scranton.

• Penguins defenseman Sam Girard appeared in his 600th career game.

• In addition to Crosby and Malkin, Penguins forwards Kevin Hayes and Blake Lizotte were scratched because of undisclosed injuries.

• Penguins defensemen Ryan Graves, Ilya Solovyov and Jack St. Ivany were healthy scratches.