"I think we finally got rewarded for the things we've been doing," Duchene said. "We've had some tough stretches defensively and offensively, but we've been doing a lot of good things for a while and it hasn't been going in. It's nice to see that happen tonight, we had a lot of guys step up for us.
"Once we made it 5-4 I think we felt like we were going to win the game."
Brassard scored from along the goal line to make it 5-3. Duchene made it 5-4 of the third on a rebound off a shot by Bobby Ryan, and Hoffman scored his first goal in 15 games to tie it 5-5 on a one-timer.
"We turned pucks over," Couture said. "We didn't forecheck and we made a lot of mistakes in our own end. We knew they were going to be coming and for some reason we just continued to turn pucks over.
"I just don't think any line stepped up and had a good shift. It was just bad shift after bad shift and it snowballed."
San Jose scored three goals in the second period. Tierney and Burns scored power-play goals 1:51 apart; Tierney scored off a rebound in the slot at 2:02 for a 3-1 lead, and a shot by Burns deflected off Senators forward Zack Smith at 3:53 to make it 4-1.
After Mark Stone scored his 16th of the season on the power play at 4:59 to make it 4-2, Hertl scored his second of the game on a wraparound off Anderson's stick at 13:27 to make it 5-2.