Defenseman Jack Johnson and Anze Kopitar scored power play goals for the Kings, who lost their fifth straight game (0-3-2).
On Thursday, San Jose dug itself a 2-0 hole in the first 2:04 before rallying to beat Pittsburgh 4-3 in a shootout. Then on Saturday, they built a 3-1 lead but lost 4-3 to Nashville in overtime.
After spotting the Kings a 1-0 lead early in the second period Monday, the Sharks scored the next four goals to take control.
"It's one of our more complete games," McLellan said. "There were still segments in the game, but it's hard to paint the perfect picture. I thought we recovered when we were pushed. We found ways to get back into the game when we were behind. Everybody got a chance to contribute, so it was a complete game, or as close as we've come to one."
Sharks goalie Antti Niemi, who was pulled after giving up those two goals against Pittsburgh, made 29 saves, 14 in the first period. Kings goalie Jonathan Quick, who came into the game with a stellar 1.68 goals against average and .941 save percentage, faced a season-high 38 shots and stopped 34 of them.
"I thought we outplayed them in the first," Quick said. "It was probably one of our best periods of the year, then we scored a goal and took the foot off the gas a little bit. We gave them the power plays, and they are a very talented team."
Monday night's game marked the first meeting between the Sharks and Kings since they met in the first round of the playoffs last season. San Jose needed six hard-fought games to beat the Kings in the first-ever postseason meeting between the two teams. The Sharks won three overtime games. In Game 3, with the series tied, San Jose overcame a 4-0 deficit to capture a 6-5 victory.
San Jose didn't have to work nearly that hard this time to dispatch the Kings. Couture's goal, which came at 6:40 in the third, put the Sharks up 4-1.
"It was a key goal, especially after the game against Nashville when we gave up that two-goal lead in the third," said Couture, who took a cross-check to the back of the head earlier in the game from Kings defenseman Willie Mitchell. "It was one we needed. (We) started the third period the right way this time.
"It's always nice to score. I like playing against L. A. I like the rivalry. They don't like us, we don't like them. Scoring a goal and helping the team win is special."
After a scoreless first period, Johnson put the Kings ahead 1-0 with a 5-on-3 power play goal, as he ripped a long-range shot past Niemi at 6:19 of the second.
After that, it was all Sharks in the period.
First Thornton, then Marleau and, finally, Boyle scored in succession, giving San Jose a commanding 3-1 lead.
The Sharks outshot the Kings 21-8 in the second after being outshot 14-7 in the first.
Thornton got the Sharks even when he scored his fourth goal of the season at 11:39. Positioned just right of the crease, he backhanded a shot off Quick's left pad and into the net. Fifty-six seconds later, Marleau made it 2-1. Racing down the left wing, Marleau turned on the jets, split a pair of defenders then knifed toward the crease. Boyle sent the puck toward the net, and Marleau, who had his first three-point night of the season, redirected it off a helpless Quick’s pads and into the net at 12:35.
Then it was Boyle's turn to score at 17:02 on the power play with a 5-on-3 edge. Joe Pavelski, positioned in front of the net, passed to a wide-open Boyle in the high slot, and he crushed a shot past Quick, beating him high as he was low on the ice, leaving most of the net wide open.
"I felt like I've been playing tennis with a tennis ball most of the year so far," Boyle said after his first goal of the season. "The puck's been bouncing around a lot. With an open net like that, everybody in the building expects you to put it in, but sometimes those pucks bounce around, so it was nice to get rewarded finally for putting the puck on net."
Even though the Sharks were just 1-for-6 on the power play, they kept the pressure on Los Angeles, especially in the second period when they had four of them.
"We came out and we had a real good first period, especially in this building," Kings defenseman Matt Greene said. "We tried to build on the things we wanted to do, and then obviously we got in penalty trouble. This (San Jose) team, that's their M.O. They feed off the power play. It gives them momentum, gives them confidence, gets them going.
"It just turned the tables on us right there, and they started picking up their game. They've got a good team over there, and they started picking up their game and we gave them every opportunity. In the third, we tried to bounce back. We had a better third, but still it was too little, too late."
Couture made it 4-1 Sharks at early in the third, knocking a rebound past Quick.
Kopitar answered with a power play goal at 8:28, taking advantage of the Sharks' struggling penalty kill and cutting the lead to 4-2.
Niemi missed the entire preseason slate and the first three regular-season games after undergoing surgery to remove a cyst near his knee, and he has struggled to find his groove. He entered Monday night's game with a 3.09 goals against average and a .892 save percentage.
But he quickly made it clear that he was on his game when he stopped a blast from Kings forward Dustin Penner less than a minute after the puck dropped. A minute later, Kopitar intercepted a pass during a Sharks power play, headed the other way and unleashed a shot, but Niemi rejected that, too.
"Nemo … he's looking sharper every night, isn't he?" McLellan said. "He's looking good. He's starting to get comfortable in there. He's starting to feel good. His timing and his reads of rushes and plays is getting better all the time. I think we're getting there."
Penner, still searching for his first goal, sent three dangerous shots at Niemi in the first period as he returned to the second line from the third. His best chance came on a breakaway, when he fired from close range. Then in the final minute, he sent a hard shot from the crease that Niemi caught.
"I think getting a good start, getting those shots there, it was easier for me," Niemi said of his solid performance.
With his two points, on a goal and an assist, Thornton now has 1,014 for his career. He moved past his childhood idol Pat LaFontaine and into a tie with Jarome Iginla for 73rd on the NHL's all-time list.
"Pat, he was like my favorite player growing up," Thornton said. "I had a chance to get an autograph when I was about 10 years old. Yeah, I was always him playing road hockey. He was my guy. He was a force back in the 80s and 90s. It was a big honor."
1 - 0 LAK
Backhand shot -
1 - 1 Tie
2 - 1 SJS