Jarnkrok gave the Maple Leafs a 4-2 lead at 9:39 of the third period, scoring on a breakaway after receiving a pass by Matthews during a 2-on-1, before Tkachuk cut it to 4-3 at 10:42 off a centering pass from Stutzle.
"They were buzzing all game," Murray said of the Senators. "They were pushing incredibly hard and throwing a lot at the net. They came hard all through the third period. Credit where credit's due."
Ottawa thought it had tied it 4-4 at 18:08 when Alex DeBrincat one-timed a cross-ice saucer pass from Claude Giroux during a 6-on-5, but the goal was overturned when Toronto used a coach's challenge for offside.
Tkachuk did tie it 4-4 with 11 seconds remaining during a 6-on-4, scoring from near the right post after a shot by Giroux deflected off the leg of Maple Leafs defenseman Jake McCabe to him.
"[Tkachuk] brought it when chips were down," Smith said. "He finds a way, and then he beats the goalie there in overtime, hits the [crossbar at 3:29]; could've been over right there. He did everything he could to help us win."
Alex Kerfoot scored the deciding goal in the ninth round of the shootout.
"You just try to hold the fort as long as you can," Murray said. "By the end of it, I kept my head down when Kerfoot went in. I had my head kind of buried in my hands. I wasn't watching, just listening."