Edmonton's Leon Draisaitl had his point streak end at 13 games. He had 10 goals and 18 assists during the streak, which is tied with Colorado Avalanche center Nathan MacKinnon and Boston Bruins forwards Brad Marchand and David Pastrnak for longest in the NHL this season.
Toffoli got his first multigoal game and first three-point game of the season when he scored on the power play to make it 5-1 with 2:59 remaining.
Toffoli gave the Kings a 1-0 lead 1:32 into the game with a wrist shot from the left face-off circle over Smith's left shoulder on the rush off Carter's one-touch pass at center ice.
Kopitar made it 2-0 at 14:21 with a slap shot from the left circle.
Carter gave Los Angeles a 3-0 lead with four seconds left in the first when he scored on the rebound of a Carl Grundstrom shot.
"The goal right at the end of the first period is a poor goal to give up," Oilers coach Dave Tippett said. "Five seconds left, we have control of the puck at the offensive blue line, and we give up a goal. That as kind of a microcosm of where we were tonight: not good enough."
McDavid cut it to 3-1 38 seconds into the second period, scoring for the second straight game after stealing the puck from defenseman Ben Hutton in the Kings zone. He has 10 goals and 11 assists during his point streak.
It was the lone bright spot for the Oilers' top line. McDavid, Draisaitl and Zack Kassian were on the ice for each of the Kings' first three goals, and Draisaitl singled himself out for criticism afterward.
"But again, you know, if your supposedly best player, players, play the way I did, you're not going to win many games," said Draisaitl, who is tied with McDavid for the NHL lead with 44 points.
Amadio, playing his 100th NHL game, gave Los Angeles a 4-1 lead at 11:16. Tippett challenged for goaltender interference, claiming Kings forward Kyle Clifford pushed Gaetan Haas into Koskinen, but the goal was upheld by video review, and Edmonton was assessed a delay of game penalty.
