Patrik Berglund and Jake Allen helped the St. Louis Blues move into a tie for first place in the Central Division.
Berglund scored the shootout winner in the 11th round and the Blues beat the Senators 4-3 on Tuesday night.
The Blues are tied with the Chicago Blackhawks and the Dallas Stars with 83 points in the Central.
Trailing 3-0, the Senators scored three unanswered goals to force overtime, including a goal by Jean-Gabriel Pageau with less than a second left in the third period.
Allen said this was one of the stranger shootouts he's been involved in.
"That's probably the longest I've been without a goal on either side," he said. "Usually if they go that long there's a couple goals in between, but it's the way it goes. Sometimes you can't stop any and sometimes you can stop them all."
Ottawa goaltender Craig Anderson made 28 saves on 31 shots before leaving the game at the 13:41 mark of the second period.
Andrew Hammond stopped 17 shots in relief of Anderson and made a number of huge saves to keep the Senators in the game. It was Hammond's first appearance since Feb. 11.
"It's always tough coming off the bench, but felt like I was prepared for it," Hammond said.
"I've been working hard in practice lately and even though I haven't necessarily been playing in the games I've been doing everything I can to be ready. I learned the lesson last year that anything can happen so I felt like I was ready for the situation."
Ryan Dzingel also scored for Ottawa.
Jaden Schwartz, with a goal and two assists, led the Blues, while Dmitrij Jaskin and Vladimir Tarasenko also scored. Allen stopped 40 shots.
Trailing 3-1, the Senators rallied in the third period.
Hammond stopped Tarasenko and Berglund and then Pageau had his first goal of the game with 2:41 remaining in regulation. He banked a shot off Allen from behind the goal line.
"The second goal was my fault," Allen said. "That can't go in at this time of year."
Pageau then forced extra time, scoring with less than a second left on the clock to send it to overtime.
"It was a good feeling, but it's unfortunate that we didn't get out with the two points," Pageau said. "We battled until the end, but at least we got one."
Down 2-0, the Senators showed a little life early in the second as Mike Hoffman had a couple of great chances, but was unable to beat Allen.
St. Louis made it 3-0 with its second power-play goal of the game as Tarasenko ripped a shot past Anderson near the midway point of the second.
Ottawa got on the board at 12:32 of the second as Dzingel scored his second of the season grabbing a loose puck out front to beat Allen.
Anderson left the game at 13:41 with what appeared to be a lower body injury. He will be evaluated Wednesday.
Once again the Senators had a poor start to the game as they were down 2-0 after 20 minutes and outshot 19-10. Ottawa is 12-25-6 when allowing the first goal.
"At the end we gave ourselves the chance to get it, but I didn't think we played good enough from the start," Senators captain Erik Karlsson said. "We played a better team from 40 minutes and in and that was the difference.
"We got lucky (Tuesday) with two late goals, especially the last one. Unfortunately we put ourselves through that situation."
Jaskin opened the scoring as he won a battle in front and was able to send a shot past Anderson at 3:36.
Schwartz made it 2-0 on the power play midway through the period as he grabbed a rebound out front and beat Anderson low stick side.
NOTES: Senators C Kyle Turris will be out indefinitely with a high ankle sprain. D Patrick Wiercioch was a healthy scratch. The Blues are without G Brian Elliott (lower body), Steve Ott (hamstring), Alexander Steen (upper body) and Jori Lehtera (upper body). D Robert Bortuzzo was a healthy scratch.