Islanders center Mathew Barzal looks at the puck during the first...

Islanders center Mathew Barzal looks at the puck during the first period of an NHL game against host Chicago on Sunday. Credit: AP/Nam Y. Huh

CHICAGO — This feel-bad loss to NHL-worst Chicago — a downer despite the returns of winger Mathew Barzal and defenseman Adam Pelech to the Islanders’ lineup after long-term injury absences — didn’t cause Patrick Roy to reminisce about smashing goalie sticks in anger, as he did after the first game of this home-and-home series.

But it did leave the coach lamenting mistakes that can’t be made, a power play that couldn’t convert and efforts that are less than 60 minutes.

“It was a grind game,” Anders Lee said, echoing Roy’s sentiments. “It’s a kick in the pants that they get an extra shot to go at the end.”

Chicago beat the Islanders, 5-3, on Sunday afternoon at United Center, with Connor Bedard getting around defenseman Dennis Cholowski for the winner at 19:06 of the third period after the Islanders needlessly iced the puck. Connor Murphy added an empty-netter.

Meanwhile, the Islanders (12-13-7) went 0-for-4 with seven shots on the power play against Chicago’s fourth-ranked penalty kill, blowing a chance to go ahead after Ryan Donato was called for tripping at 16:40 of the third period.

Teuvo Teravainen’s five-on-three power-play one-timer had given Chicago (10-19-2) a 3-2 lead at 15:19 of the second period after Alexander Romanov shot the puck over the glass for a delay of game with Maxim Tsyplakov already in the penalty box for tripping.

“It’s too bad,” Roy said. “There’s mistakes you can make, but there are some you cannot make and it will cost you at some point. That cost us.”

Ilya Sorokin made 18 saves in his eighth straight start.

The Islanders beat Chicago, 5-4, at UBS Arena on Thursday night and drew Roy’s wrath for not competing hard enough in the third period after taking a four-goal lead.

Noah Dobson, skating between the circles, tied Sunday’s game at 3 just 47 seconds into the third period on a goal that withstood a goalie interference challenge by Chicago interim coach Anders Sorensen, who believed Tsyplakov had made contact with Arvid Soderblom (30 saves).

“Our coaches were pretty convinced that it would be a good goal,” Dobson said. “But you never know these days.”

The unsuccessful challenge led to the Islanders’ third power play. The puck movement was good, but the Islanders mainly were forced to the outside as Chicago packed it in around the crease.

After giving up the first goal for the seventh straight game, the Islanders trailed 2-1 after the first period. Ilya Mikheyev stepped behind Cholowski at the crease to open the scoring at 9:08. Defenseman Ryan Pulock, with his first goal of the season, tied it at 1 from the point at 18:43. Simon Holmstrom, using his leg to deflect in Pierre Engvall’s feed, tied it at 2 at 2:25 of the second period.

The Islanders activated Barzal (upper body) off long-term injured reserve on Sunday and Pelech (jaw) off injured reserve.

“The hardest part about getting injured is having to take a little time off and then getting those lungs back and your legs back,” said Barzal, who was a minus-2 in 20:45 as he centered Lee and Jean-Gabriel Pageau and took two shots. “The biggest thing is just the mental battle. Not being around the boys as much. Not being on the road. Not being in the fight with the boys.”

Barzal missed 21 games and last played on Oct. 30. Pelech, who was hurt in the next game on Nov. 1 in Buffalo as he was hit in the face with a puck, said he went a couple of weeks without being able to eat solid food and is wearing an additional protective shield for his jaw.

“I think I knew right away because I could feel it in my mouth that things weren’t really where they were supposed to be,” said Pelech, who logged 19:47 on Sunday with four hits and two blocked shots.

Notes & quotes: Semyon Varlamov was placed on injured reserve with a lower-body injury. The goalie last played on Nov. 29 ... Defenseman Scott Mayfield skated in his 500th NHL game. It marked the first time in team history the Islanders had three defensemen in their lineup who had played at least 500 games, including Pulock (518) and Pelech (512) ... Rookie defenseman Isaiah George was a healthy scratch for the first time. Defenseman Grant Hutton remained a healthy scratch.