Colorado defenseman Jack Johnson had an open net on a wraparound, but Sam Carrick used his stick blade to save a goal at 2:39 of the second period.
Carlsson scored from the slot off a backhand feed from Killorn 19 seconds later to cut the lead to 3-2 at 2:58 of the second period.
Killorn tied the game 3-3 at 10:22 of the second period with a wrist shot from the right circle with one second left on a power play. It was his 200th NHL goal.
"We had some self-inflicted mistakes in the second," Colorado coach Jared Bednar said. "But in the third, I thought we played really well. We had two breakaways, some real nice tip plays in the net front, some scrambles, but couldn't get the go-ahead goal."
Colorado defenseman Cale Makar, who is tied for fourth in the NHL with 34 points, did not play the end of regulation or overtime because of an undisclosed injury. Bednar did not have an update after the game.
Ducks forward Mason McTavish left the game with an upper-body injury late in the first period after he was hit by Manson. He is second on the Ducks in goals (10) and points (21). Cronin did not have an update.
NOTES: Killorn has two goals in 14 games this season and had 198 in 815 games with the Tampa Bay Lightning. … It was the third two-goal game of Byram's NHL career (Feb. 18, 2023 against St. Louis Blues; Nov. 3, 2021 against Columbus Blue Jackets). … Colorado defensemen have scored 19 goals this season, one behind Montreal for the most in the NHL. ... Avalanche forward Valeri Nichushkin had his NHL career-high nine-game point streak end (eight goals, five assists). ... Colorado had won 13 consecutive games in California and was 10-1-0 against Anaheim in its past 11 games. ... The Ducks have allowed a goal on the opponent's first shot the past two games and have allowed a combined seven goals in the past two first periods.