He created goals by linemate Pat Maroon 64 seconds after the start and by Milan Lucic on the power play at 12:47.
McDavid darted and danced on the attack with his exceptional speed and hands, and he was dangerous nearly every time he touched the puck.
"I'd like to play him for 60 minutes, but I think we'd run him right into the ground," Oilers coach Todd McLellan said. "He was exceptional, I thought, all night, like he usually is, but in that first period, he had it on a string and he made some tremendous plays.
"I don't know what else you can say about him. He went head-to-head against their best and did a great job."
With his monster first period, which included four shots on goal and nine attempts in eight shifts, McDavid reclaimed the NHL scoring lead. The Oilers captain has 82 points (25 goals, League-leading 57 assists), two more than Sidney Crosby of the Pittsburgh Penguins.
The win has the Oilers (39-24-9, 87 points) tied with the Anaheim Ducks for second place in the Pacific Division, four behind the first-place San Jose Sharks, with 10 games left, putting them well within striking distance of their first Stanley Cup Playoff appearance since 2006.
McDavid made a statement with his first shift Monday, stripping the puck from Kings center Jeff Carter in the neutral zone.
McDavid's right wing Leon Draisaitl took the turnover and fed the puck back to him as he crossed the blue line with speed. McDavid waited a moment before taking a wrist shot that goalie Jonathan Quick stopped with his blocker.
The puck went high into the air, and left wing Patrick Maroon waited for it to fall far enough to legally bat it into the net from near the edge of the crease.