CHICAGO — David Quinn declared Thursday’s game the first of the season in which his Rangers’ effort was “just not acceptable.”

So forget that the scoreboard might have shown it was a one-goal game with under five minutes left in regulation. Forget the players lamenting the ringing of pucks off crossbars, or the untimely breaking of sticks. Forget the facade the Rangers hung with one of the NHL’s top-tier teams at this early juncture in the season.

Instead, focus on how the first-year coach described the 4-1 loss to the Blackhawks at United Center in candid and graphic detail. It was a difficult pill for his team to swallow as they started a four-game road trip that heads to California.

“That was, really, probably as poor as we played all year,” Quinn said. “One of the things I think we’ve done a good job of is skating and competing, and that wasn’t the case tonight. We have to get back to work on Saturday. That was just not acceptable.”

The Rangers (3-6-1) were coming off their first regulation win of the season, a 5-2 victory Tuesday over the Panthers at the Garden. That game finally saw them convert on their offensive chances. But stepping up in class to the Blackhawks (6-2-2) was a gruesome wake-up call.

The most appalling piece of it all might have been the one shot on goal — one! — the Rangers had in the third period, after trailing 2-1 following the second intermission. Any semblance of their scrappy, hard-working identity seemed to go out the window in that desultory closing 20 minutes — even if Kevin Hayes hit a crossbar with a shot that could have tied the game with 6:30 remaining in regulation.

“We just didn’t have enough people competing, shift in and shift out,” Quinn said. “We certainly didn’t take away time and space on them. We just weren’t good enough in any area.”

No one is going to confuse these Rangers with some of the most talented teams in the league. No one is going to confuse them even with one of their own past images — unless looking at goalie Henrik Lundqvist, whose brilliance continued while he gave his team a chance in making 33 saves.

But there was little Lundqvist could do when Brendan Smith’s stick somehow broke, allowing Alexandre Fortin to be left unchecked at the far post to tap in a cross-crease pass from Nick Schmaltz at 10:33 of the second period. That gave Chicago a 2-1 lead and from there, the Blackhawks sat back, played with the puck, and hardly gave the Rangers a sniff for any sustained offensive pressure.

“They’re a different team, they play different than any other team we play against,” said Mika Zibanejad, whose top line with Chris Kreider and Mats Zuccarello was practically invisible. “They really like just having the puck. I feel like it looks prettier than it actually is. It doesn’t result in anything, but it’s this chasing game all the time.

“When we do get it, either we spend an awful lot of time in our zone, just trying to get it out and change and we give it right back to them. Or we want to make something out of it and try plays that aren’t there, or not executing on our plays.”

The game started on an ignominious note, as Brady Skjei and Adam McQuaid tripped each other up and allowed Jonathan Toews to run in a breakaway and beat Lundqvist for a 1-0 lead just 2:55 in. It only took the Blueshirts 74 seconds to tie it, 1-1, when Pavel Buchnevich got his third of the season on a juicy rebound left by goalie Corey Crawford.

But there wasn’t enough when the Rangers needed it the most. Patrick Kane got his ninth goal in the first 10 games when he jammed one in to make it 3-1 with 4:21 remaining in the third, and Alex DeBrincat got his eighth of the season by pouring one into the empty net.

Now the Rangers head to the California sunshine looking to recapture that good feeling, which proved to be incredibly fleeting.

“It’s frustrating and disappointing,” Zibanejad said. “We felt [good] about ourselves coming in here, and this happens.”