Jeff Carter gave the Kings a 2-1 lead at 16:17 of the second period when he redirected Michael Amadio's point shot past Varlamov in front on the power play.
"That comes from everyone on the bench, the coaches, too," Kings defenseman Ben Hutton said. "They're staying stick with the game plan. Stick to the systems and things are eventually going to go our way. And that's exactly what happened, you know. Got a power play, we get a nice goal and then we got the lead and just kept chipping away, chipping away and a nice two points."
The Kings largely controlled the second period with an aggressive forecheck and sustained possession in the offensive zone, but Trotz said the Islanders had worked their way back into the game before Noah Dobson tripped Kyle Clifford at 14:33.
"We were quick, we were really pushing, and then we took a penalty when it's really got to be an execution play," Trotz said. "It's a D-to-D pass, we fumble it, we end up in the box. They score and I thought gave them all the momentum at that point."
Matt Roy made it 3-1 at 10:19 of the third period with a one-timer from the point during a 4-on-4, and Iafallo scored into an empty net at 17:53 to extend the lead to 4-1.
"I think in this League, if you get a lead in the third, you better hold onto it," Kings forward Blake Lizotte said. "So I think we stay patient with our system and gain lines. That's the most important thing is not turning the puck over on our blue line, especially with the lead in the third period. When you got the lead, you got to make smart, hard plays, and I feel we've done that for the most part when we had the lead going into the third."