Newhook finished off a 2-on-1 rush for the 4-3 lead after the Ducks turned the puck over in the offensive zone during 4-on-4 play.
Vatrano tied it 3-3 at 11:31 of the third with a wrist shot off a criss-cross play with McTavish, his 13th goal of the season.
"I honestly liked our third, we had a lot of chances," McTavish said. "I thought [Gibson] was great today too. It’s just the way it goes, there’s a lot of games and you can’t get too down on yourself and hopefully we get out of this little losing streak."
Newhook gave Montreal a 1-0 lead at 5:59 of the first period. Tanner Pearson made a seam pass to Newhook in the slot, and he settled the puck before scoring with a wrist shot. The goal came six seconds after the Ducks killed off the first power play of the game.
Kaiden Guhle made it 2-0 just 38 seconds later. Anaheim lost possession in the neutral zone, and Evans made a short pass to Jesse Ylonen to spring a 2-on-1 break. Ylonen fed the puck ahead to Guhle, who scored with a redirection from in front of the crease at 6:37.
"I think it gave guys confidence," Evans said of the early lead. "I feel like we were coming in waves at the beginning too, and everyone's got a lot of confidence to make the right plays."
McTavish made it 2-1 with a power-play goal 53 seconds into the second period. Leo Carlsson fed McTavish for a redirection from in close just five seconds into the man-advantage.
Mike Matheson restored the two-goal lead for Montreal 56 seconds later, receiving a pass just inside the blue line with room to skate in and score with a wrist shot to make it 3-1 at 1:49.
The Ducks couldn't capitalize on back-to-back odd-man rushes, but they did on their third when McTavish scored at 6:00 off a spinning feed from just above the goal line by Vatrano, cutting it to 3-2.