Ottawa forward Brady Tkachuk had an assist in his first game since Oct. 13 after missing 20 games with a broken right thumb.
“It was nice to get back and play and not overthink anything,” said Tkachuk, the Ottawa captain, who had a game-high eight shots on goal in 17:12 of ice time. “It’s a game having the lead going into the third period, so we’ve got to find a way.
"I would have felt a lot better with a win, but it was just nice to get back. Grateful to be playing again but disappointed with the result.”
Kessel made it 4-3 at 9:19 when he backhanded a rebound in the crease. The goal capped a five-second flurry that saw Dylan Holloway get stopped by Merilainen, Pius Suter have a rebound attempt blocked by Senators defenseman Nick Jensen, and Holloway get denied again.
Sundqvist’s first of the season, in his 16th game, put the Blues ahead 1-0 at 7:59 of the second period. He collected a rebound off the end boards and banked a shot in off Merilainen from the side of the net.
Pinto tied it 1-1 at 10:11 when he swept a rebound past Binnington, who had stopped Nikolas Matinpalo from in close.
Zetterlund put the Senators in front 2-1 at 18:26. He gathered a loose puck behind the Blues net and looked as if he was going to bring it out at the right post, but he changed direction and tucked it inside the left post instead with Binnington leaning the other way.
Kyrou tied it 2-2 at 2:01 of the third period when he went to the backhand and lifted the puck into the top left corner off a Jake Neighbours cross-ice pass.
“It was just great patience by [Neighbours],” Kyrou said. “Kind of hold it and wait for the lane to open up. It was a [heck of a] pass.”