Portillo, a third-round pick (No. 67) by the Buffalo Sabres in the 2019 NHL Draft, was recalled from Ontario of the American Hockey League on Sunday to replace Darcy Kuemper, who has been on injured reserve since Nov. 15 because of an undisclosed injury.
"It was just a lot of different emotions," Portillo said of his debut. "I just tried to stay calm and prepare the same way and stick to my routine."
Alex Laferriere broke a tie early in the third period and had an assist, and Alex Turcotte also scored for the Kings (13-8-3), who won their second straight after alternating wins and losses over their previous six games.
Ryan Strome scored, and John Gibson made 16 saves for the Ducks (9-10-3), who had won four of six (4-1-1).
"The last 10 or 11 games we haven't had too many stinkers," Anaheim coach Greg Cronin said. "We had some, maybe, periods that were off, but I think for the most part we've played really well as a group."
Kings forward Adrian Kempe and Ducks forward Trevor Zegras each hit the crossbar 15 seconds apart in the final minute of a scoreless first period.
Strome gave Anaheim a 1-0 lead at 2:48 of the second period. Ducks defenseman Drew Helleson took a wrist shot from above the left circle that Strome tipped on the way to the net while being closely defended by Kings forward Phillip Danault. Portillo made the save, but the rebound came back out to Strome, who backhanded the puck into the net.
"I just thought that we had the puck maybe more than we have had in the past against these guys," Strome said. "In the past, I feel like we have been on our heels and they kind of come in waves at us, but tonight we were kind of pushing the pace on them."
Turcotte tied it 1-1 at 10:46, scoring short side off a pass from Laferriere on a 2-on-1. Zegras attempted a horizontal pass in the neutral zone to Mason McTavish, but it was out of his reach and intercepted by Laferriere.
"I hadn't had a shot on goal in two games, so no question I was shooting that," Turcotte said. "I think the goalie maybe thought I was going to give it back to (Laferriere) and left the top left corner."
Laferriere gave Los Angeles a 2-1 lead at 1:18 of the third. Danault drove to the net and his shot from along the goal line was poked out by Gibson's stick, but Laferriere skated in and scored on the rebound.