Rangers center Vincent Trocheck, right, reacts as St. Louis Blues...

Rangers center Vincent Trocheck, right, reacts as St. Louis Blues players, back left, celebrate after a goal by left wing Pavel Buchnevich as during the first period of an NHL game Sunday in St. Louis. Credit: AP/Jeff Le

ST. LOUIS — The losses don’t stop for the Rangers. Each is more stunning and more frustrating than the last.

On Sunday, things got even harder. They were forced to play the opener of their three-game road trip without leading scorer Artemi Panarin, who was scratched against the Blues because of an upper-body injury.

The Rangers already were without defenseman K’Andre Miller, who missed his second game while on injured reserve with an upper-body injury. Coach Peter Laviolette, desperate to do something, anything, to change the team’s fortunes, also scratched forward Kaapo Kakko, who has been having one of his best seasons and had been part of the team’s most consistent forward line.

Asked why he scratched Kakko, Laviolette said, “We were putting fresh legs in the lineup tonight.’’

Ultimately, the result probably was predictable. The Rangers lost, 3-2, to the Blues and old friend Pavel Buchnevich at Enterprise Center. They dropped both ends of their weekend back-to-back and have lost four of their last five and 10 of their last 13.

“I don’t even know how to describe the feeling right now, but it’s definitely not good,’’ a frustrated Adam Fox said. “I mean, we talk. We talk as a group and say to just try and be engaged and that. But yeah, it definitely wears on you when you’re in kind of a streak like this.’’

“It’s frustrating,’’ Laviolette said. “It’s a loss. We pressed in the third period, couldn’t get it done.’’

The Rangers (15-14-1) at least showed a little spunk in the third period. They trailed 3-0 entering the period on goals by Buchnevich in the first and Jordan Kyrou and Robert Thomas in the second, but rookie Brett Berard and second-year man Will Cuylle scored 1:19 apart midway through the third to give them a chance.

“I don’t know. It’s hard right now to find positives,’’ forward Alexis Lafreniere said. “But we didn’t quit at the end, so maybe we’ll try to build on that and bring it to next game.’’

Buchnevich, whom the Rangers traded to St. Louis in 2021, swept in a pass from Jake Neighbours that went past defenseman Chad Ruhwedel and goalie Jonathan Quick and sneaked inside the right-wing post at 18:51 of the first.

Kyrou made it 2-0 at 6:33 of the second period. Ryan Lindgren whiffed on a clearing attempt near the Rangers’ blue line and Kyrou scooped up the puck and scored on a breakaway against Quick. Thomas beat Quick with a shot on a two-on-one to make it 3-0 at 10:28.

Berard’s goal, at 10:18 of the third, came off what seemed to be a nothing play. He got to a loose puck at the top of the slot after Vincent Trocheck’s shot was blocked, pushed the puck into the left circle and whipped a shot past goalie Joel Hofer for his second goal.

Cuylle made it 3-2 with his 11th goal when he took a pass from Lafreniere and slammed it home from the mid-slot.

Panarin, who leads the team with 15 goals and 36 points, had been spotted in the locker room in recent days with an ice pack on his shoulder. In Saturday’s 5-1 loss to the Los Angeles Kings, he played a season-low 14 minutes and 22 seconds.

With Panarin and Kakko (four goals, 10 assists, plus-10) not in the lineup, the forward lines were radically different than they had been.

Filip Chytil centered a top line between Lafreniere and Cuylle, Trocheck skated between Jonny Brodzinski and Reilly Smith, Mika Zibanejad centered a third line between Jimmy Vesey and Berard, and Chris Kreider was dropped to the fourth line with Sam Carrick and rookie Adam Edstrom.

Ruhwedel also entered the lineup in place of rookie Victor Mancini, who had been minus-3 on Saturday.

Before the game, Laviolette was asked if he needs the team’s best players — players such as Zibanejad, Kreider and Fox — to play better than they have.

“We do, yeah,’’ he said. “When we’re not winning hockey games, we have to account for everything and everybody. And so I do think that it starts with the guys that take down the [most] minutes, the guys that can really have an impact.’’

Zibanejad, who has struggled this season, played a season-low 13 minutes and four seconds.