Kings back into first-round playoff matchup with 4-2 loss in season finale

A heavy dose of Benn-adryl sent the Kings into their playoff destination.

A season’s worth of work to decide their postseason fate was essentially decided when their defense fell asleep in a six-minute span Saturday.

That’s how long it took the Dallas Stars’ Jamie Benn to record a natural hat trick, in the first period, and the Kings finished with a 4-2 loss that translated to a first-round playoff matchup with the Vegas Golden Knights as the first wild-card team.

The Kings will go into it with points in eight of their final 10 games, but only their second regulation loss since March 17 will sting a bit, and they know they can’t afford lapses like that in a best-of-seven series.

“Obviously it’s not a good enough start,” defenseman Alec Martinez said. “Quite frankly, it’s embarrassing. We left our goalie out to dry. That’s not fair to him.”

Martinez’s two second-period goals couldn’t negate Benn, who recorded three straight goals on a redirect of Alexander Radulov’s shot-pass on a rush for a 4-0 lead that triggered one lone hat thrown onto the ice amid a smattering of boos at Staples Center.

It was an ominous sign when Stars forward Devin Shore knocked the puck free from Christian Folin and skated in to beat Jonathan Quick with a backhand nearly seven minutes into the game for the first goal.

“I think they came out way harder than us,” winger Adrian Kempe said. “Obviously they’re not in a playoff spot, so, I mean, I don’t know if we were thinking about that before the game, but, I mean, it wasn’t a good start.”

The Kings were horrible in their own zone and around their net to start. They were charged with six giveaways in the opening period, and it was fair to wonder whether Quick would remain in the game.

He did, and the Kings righted themselves with a pendulum-swing second period that produced Martinez’s two scores. The Kings consistently set up shop in the Stars’ end, and Martinez was open to one-time the puck through a thicket of players to break the shutout early in the second period.

Martinez pulled the Kings to 4-2 on a great feed from Michael Amadio just after a Dallas penalty expired. The Kings outshot the Stars 18-2 in the period.

The Kings’ defense won’t be at full strength to start the playoffs. Derek Forbort has been ruled out and Jake Muzzin remains a question mark after he skated on his own in the morning.

But the Kings seemed ready for the serious hockey to begin, against the expansion Pacific Division-champion Golden Knights.

“It will be a really good matchup,” Martinez said. “It’s a tough building to play in, so you know, especially in a playoff atmosphere, the arena’s going to be buzzing. That said, I think Staples will be, too. It’s two good hockey clubs going at it.”

Oscar Fantenberg played his first game since Jan. 4. Torrey Mitchell remained ill, coach John Stevens said, and was scratched. Jonny Brodzinski was recalled and played on the fourth line in place of Andy Andreoff.

curtis.zupke@latimes.com

Twitter: @curtiszupke