The Kings (5-11-1) lost their third straight game since winning Desjardins' debut by defeating the Anaheim Ducks 4-1 on Nov. 6.
Kadri put the Maple Leafs ahead 1-0 at 2:42 of the first period. Marner found Kadri in the slot for a shot into an open net to cap a crisp seven-pass sequence in the Kings zone.
Tavares made it 2-0 at 6:12 when he tipped Rielly's shot from the blue line past Budaj. Tavares has scored in three straight games and has four goals and five assists during a six-game point streak.
"We're 18 games in, and he's been outstanding," Reilly said of Tavares, who is in his first season with Toronto. "He's been a leader, he's been a 200-foot player, he's been putting the puck in the net. As far as I'm concerned, he's been exactly what we were expecting, so hopefully he can keep rolling."
Adrian Kempe redirected Dion Phaneuf's shot from the blue line to get the Kings to within 2-1 at 14:28. Maple Leafs defenseman Igor Ozhiganov turned the puck over on a blind pass from behind his own net to the blue line, giving Phaneuf an uncontested shot that resulted in his first point of the season.
Toronto scored three straight goals in 6:04 in the second period.
Rielly gave the Maple Leafs a 3-1 lead at 1:15 on a shot from the right face-off circle over Budaj's right shoulder. Rielly has two goals and three assists during a three-game point streak, including an assist in three straight.
Andreas Johnsson put Toronto ahead 4-1 at 4:33, ending Budaj's first start of the season.
Kadri made it 5-1 at 7:19 with his second goal of the night. He has scored seven goals in his past nine games.
"Nazem was great in the middle," Rielly said. "He's been good there now for a year and change. The past couple nights, we haven't been good on the power play. We've been creating chances, but it just hasn't been going in, so it was good to get rolling a little bit."
The Maple Leafs were 3-for-6 on the power play, setting season highs for power-play goals and penalties drawn. The Kings went 0-for-2.
