OTTAWA -- Dion Phaneuf scored at 1:59 of overtime to give the Ottawa Senators a 4-3 win against the Boston Bruins in Game 2 and tie their Eastern Conference First Round series at Canadian Tire Centre on Saturday.
Game 3 of the best-of-7 series is Monday in Boston.
Phaneuf scored on a slap shot from the point 12 seconds after a third-period delay of game penalty to Bruins defenseman Zdeno Chara expired.
"We didn't draw it up like that, for sure, but playoffs, it's about momentum, sticking to it, continuing to find a way to push your game," Phaneuf said.
"That's the biggest one I've scored. It feels great to do it here, in front of our fans. Just incredible. I've played a long time (12 seasons) and it's my first (playoff) overtime winner. It feels great."
[WATCH: All Bruins vs. Senators highlights | RELATED: Complete Boston vs. Ottawa series coverage]
Clarke MacArthur scored his first goal in almost two years, Chris Wideman and Derick Brassard scored, and Craig Anderson made 26 saves for the Senators, who trailed 3-1 in the third period.
Drew Stafford, Tim Schaller and Patrice Bergeron scored for the Bruins, and Tuukka Rask made 25 saves.
The Senators tied the game on goals by Wideman at 5:28 and Brassard at 7:48.
"Fairly typical," Bruins coach Bruce Cassidy said. "A team that's behind, they're at home, they're desperate, they're going to push hard and they did. We saw the same script on Wednesday (winning Game 1 2-1 after trailing 1-0). We did it to them. What's disappointing is we're generally are pretty good at closing out games."
Video: BOS@OTT, Gm2: Phaneuf drills home the OT winner
Stafford put the Bruins ahead 1-0 at 9:47 of the second period when the puck deflected to him off the skate of Senators forward Viktor Stalberg in the left-wing circle.
MacArthur scored on the power play to tie the game 1-1 at 10:57 of the second, his first goal since April 19, 2015. He returned April 4 after missing almost two seasons because of concussions.
With the Senators on the power play, Anderson gave the puck away to Bruins forward Dominic Moore and Schaller scored a shorthanded goal to make it 2-1 at 12:39.
Video: BOS@OTT, Gm2: Schaller races for a shorthanded tally
Bergeron deflected a shot by David Pastrnak at 16:02 of the second period on the power play to put the Bruins ahead 3-1.
Chara was penalized with 13 seconds left in the third period when his clearing attempt went over the glass.
"I'm trying to keep the puck in play, but whether it was a little bounce or maybe put too much on it, those things happen," he said. "It was just a bad bounce and got to make sure next time to keep it in."
Goal of the game
Ottawa defenseman Erik Karlsson showed his dynamic skating ability when he got the puck at the right point, crossed the ice and cut down the left side before whipping a pass to Brassard, who was alone in the left-wing circle, to score the third goal for the Senators.
Video: BOS@OTT, Gm2: Brassard nets Karlsson's nice pass
Save of the game
With 5:27 remaining in the third period and the game tied 3-3, Rask got his right shoulder on a point-blank shot by Zack Smith from the slot.
Video: BOS@OTT, Gm2: Rask shrugs off Smith from the slot
Highlight of the game
The crowd gave MacArthur a loud and long ovation after he scored.
"Great feeling," MacArthur said. "It was a lot of weight lifted off me, getting that. It was just great to get a goal, great to be back in the playoffs and doing what we're doing."
Video: BOS@OTT, Gm2: MacArthur buries fine passing play
Unsung performance of the game
Bruins defenseman Joe Morrow, in his first game since Jan. 22, played 19:59 and had three hits and two blocked shots. The Bruins, already thin on defense, lost Adam McQuaid with an upper-body injury in the first period.
They said it
"We've developed a soul. We've also developed a capacity to overcome adversity, during games and from game to game. And that's something we did not have at the beginning of the year at all." -- Senators coach Guy Boucher
"We want to make it 2-0. I'm not going to sit here and tell you I'm satisfied with a split. We were 20 minutes away from being up 2-0. That's the way I look at it." -- Bruins coach Bruce Cassidy
"They had their fans here. They were pretty loud, but we took a game from them. We have our fans and they'll be that much better than these guys, so hopefully we can take both games there." -- Bruins forward Tim Schaller on returning to Boston for Games 3 and 4
Need to know
Cassidy said McQuaid's status will be updated Sunday. It was the fourth game in a row the Bruins lost a defenseman; they are also without Colin Miller, Brandon Carlo and Torey Krug. ... Senators defenseman Mark Borowiecki left the game after playing 3:43 when he fell into the boards and limped off the ice. There was no update after the game. … Senators defenseman Marc Methot returned to the lineup after missing 10 games with a finger injury. … Boucher scratched forward Tommy Wingels and used Ryan Dzingel.
Game 3 of the Eastern Conference First Round at TD Garden on Monday (7 p.m. ET, CNBC, SN, TVA Sports, NESN)
Video: Phaneuf's OT goal lifts Sens past Bruins in Game 2