Jared McCann and Ryan Donato scored, and Chris Driedger made 23 saves for the Kraken (17-38-5), who have lost four in a row. Seattle scored three straight goals in the third period to tie the game.
"It's important to be able to go out there and play hard for one another and fight and compete right until the very end, whether we get a [goal] or not," Kraken coach Dave Hakstol said. "That's really important. To build and execute on that momentum and have that period where everybody fed off of each other is important."
McCann made it 3-1 at 9:14 of the third period with a wrist shot. Donato got it to 3-2 36 seconds later when he tipped Jamie Oleksiak's point shot, and Appleton tied it 3-3 at 13:01 when his bad-angle shot squeaked in short side.
"The first two periods are inexcusable. I think we knew that," Donato said. "The momentum was dead; we needed something. Jared had a big goal, and once we had that feeling of, 'We're back in this,' I think a lot of guys felt a lot better about the situation. I thought we put in a [heck] of an effort in the third period. Unfortunately it ended the way it did, but that's a testament to our character."
The Kraken looked to have scored the opening goal when Mason Appleton redirected a pass from Colin Blackwell at 8:17 of the first period, but the Senators challenged for offside and video review overturned the call on the ice, with the clock reset to 8:13.
Norris gave the Senators a 1-0 lead at 8:32 when he one-timed a cross-ice pass from Tkachuk.