Fiala beat Sogaard with a wrist shot from the point on the power play to make it 5-4 at 16:25.
MacEwen scored his second goal of the game at 17:52 to tie it 5-5.
"I thought he was great tonight," Norris said of MacEwen. "He does a lot of little things that go unnoticed, whether it's taking a hit or giving a hit, or obviously a big fight against one of the toughest guys in the league [Jeannot]. And then he scores a couple goals, kind of the cherry on top."
Laferriere scored on a partial break to give the Kings a 6-5 lead at 3:38 of the third period.
Claude Giroux tied it 6-6 at 5:25 with a backhand from in tight on the power play. Norris beat Kuemper with a wrist shot from the slot on the power play to give Ottawa its first lead, 7-6, at 9:18.
"When we were at our game, and it felt like it was most of the night, we were the better team," Tkachuk said. "Whenever adversity hit, we just stuck with it, and you get rewarded for hard work."
Jeannot chipped the puck over Sogaard's blocker to tie it 7-7 at 14:26.
"We had three pucks that bounced in off of our own guys, probably a couple that we'd like to have back," Green said. "But the resiliency that we showed, we've talked about that a lot since Day 1. Sticking with the process, and I like how we did that tonight."
NOTES: The Senators (4-for-6) and Kings (3-for-5) combined for seven power-play goals, the most in an NHL game since Jan. 15, 2014 when the Anaheim Ducks and Vancouver Canucks also combined for seven. … Ottawa scored eight goals in a game for the first time since Dec. 14, 2021, an 8-2 win at the Florida Panthers. … It was MacEwen's second two-goal NHL game (also March 6, 2020).