Seventh heaven for Kings with 6-2 rout of Ducks

When it comes to winning a big game, the Kings’ knowledge in how to do so was a mismatch over the Ducks.

That strength more than any other defined the Kings’ 6-2 victory in Game 7 of the Western Conference semifinal at Honda Center.

From an early goal by Kings forward Justin Williams — his sixth in a Game 7 — to continued veteran production, the Kings won their sixth elimination game of these playoffs and sent the Ducks home in their second in two years.

“The inner arrogance and quiet confidence that’s in this dressing room … I look around and know it’s going to get done,” said Williams, who’s now 6-0 in Game 7. “No one has to be great, but everybody has to be good.

“And we were all good tonight.”

The Kings advance to their third consecutive Western Conference finals, where they’ll have a rematch of last year’s loss to the defending Stanley Cup-champion Chicago Blackhawks with Game 1 Sunday at United Center.

The top-seeded Ducks, meanwhile, were vanquished while falling behind 5-0 and losing for the third time in four home games, in the same building where they started the season 20-0-2.

“You feel like this could’ve been the year,” Ducks forward Andrew Cogliano said. “That’s the real down part of this. This is way worse than last year, when we were nervous, and didn’t know how to play in a Game 7.”

The Ducks also blew a 3-2 series lead last year in bowing to the Detroit Red Wings in the first round. Coach Bruce Boudreau said this version will take “a few months to figure out.”

The lopsided defeat was their only four-goal home loss of the season, and the players struggled to answer why they collapsed in their moment of truth.

“That’s the question everyone in this room is asking right now,” Ducks center Saku Koivu, 39, said after failing to reach his first conference final and not committing about a return next season. “There was no question they were a different team. They outplayed us. Tough way to go home.”

The Ducks were the second-highest scoring team in the NHL this season, but they sent only six first-period shots at Kings goalie Jonathan Quick, who finished with 25 saves.

“It’s a bitter pill.… I lay a lot of that on our shoulders,” Ducks center Ryan Getzlaf said. “Nerves got to us a bit, pucks were dancing around and they were capitalizing. A 3-0 lead [after the first], you’re not going to beat the Kings.”

The decision that will be debated about Boudreau, who suffered his fifth Game 7 loss at home, was making 20-year-old goalie John Gibson his starter in the rookie’s seventh career NHL game.

“We weren’t ready from the start,” Gibson said. “I didn’t make the saves I had to make and we lost the game.”

Gibson gave up four goals on 18 shots and was sent to the bench on a blast shot past him by Anze Kopitar just 2:02 into the second period. The Ducks’ primary starter, Jonas Hiller, provided relief on his likely way out of town to free-agent riches.

Any Game 7 dram didn’t last long.

First, Ducks defenseman Ben Lovejoy went to the penalty box for hooking Kings forward Dustin Brown, then Williams followed his own shot with a backhand past Gibson 4:30 into the game.

Less than five minutes later, Kings veteran forward Jeff Carter outworked rookie Ducks defenseman Hampus Lindholm for a loose puck, then shoved a backhand to the net for a 2-0 lead.

Carter, 29, in his 10th NHL season, was playing in his fourth career Game 7. He’s never lost one.

The Ducks had a window to rally when forward Corey Perry was given a penalty shot with 5:52 left in the first. But Perry, who led the Ducks with 43 regular-season goals, never unleashed a shot as Quick poke-checked the puck away.

Just 1:04 later, the Kings pursued the fatal blow to their rival when center Mike Richards rushed through Ducks defensemen Cam Fowler and Francois Beauchemin and followed Dwight King’s shot for a 3-0 lead.

“We made a conscious decision to be more aggressive, and it didn’t work,” Lovejoy said. “We have the right pieces in here, the right coaching staff, the right goaltending. Today, we weren’t good at hockey.”

Lovejoy paused for an extended period when asked if Friday was a heart issue.

“I don’t know,” he said. “Clearly, that Kings team outplayed us. All night.”

lance.pugmire@latimes.com

Twitter: @latimespugmire