Both teams were missing key players, including their captains, as Ottawa was without Jason Spezza and the Bruins were without Zdeno Chara. Both sat out with lower-body injuries.
The Senators got off to a strong start and played well enough to hold off the Bruins.
Smith was called for a faceoff violation with 1:51 remaining, leaving Ottawa short-handed but with a 4-3 lead. Still, the Senators held off the hard-pressing Bruins for the win.
"You never want to put your team in that position, but I had faith in the guys killing and obviously Anderson was playing very well," Smith said. "That was a tough one to take. It's not a call that's called consistently so I think someone has to get on the same page about that one. If they're going to call it they have to call it all the time I think."
Anderson was solid as the Senators held off the Bruins late in the third.
"They had a 6-on-4 there and they were moving the puck pretty good and we got a couple of key blocks and that was the difference," Anderson said. "When you're out-manned like that anything can happen."
Anderson said the team wasn't feeling good after Friday's loss and says the fact they were able to rebound with a win shows a lot of character.
"It's all about how you respond," Anderson said. "It's not about what happens to you, it's how you respond, and I think we came out here and we responded in the right way. Now the key is we have to respond again going forward."
Ryan scored the winner after forcing a turnover at the Ottawa blue line and breaking in alone, beating Johnson with a high backhand.
Earlier, the Senators caught a break when what would have been Iginla's second goal of the game was reviewed and ruled to be kicked in, keeping the game tied 3-3.
Iginla said he wasn't all that surprised that the goal was called back.
"I didn't really expect it to be a goal," Iginla said. "I knew (the puck) was coming to my foot, but I was hoping it wasn't a kicking motion. At the same time I understand the call, but you're always hoping for the best for sure."
Bruins coach Claude Julien said his team played well and probably deserved a better fate.
"Our guys battled hard," Julien said. "It would have been nice to come out of here with at least a point. I thought we deserved that much with how hard we competed to get ourselves back in the game, but unfortunately that wasn't the case. "
Ottawa opened the scoring at 7:04 of the first as Wiercioch jumped into the play to grab a rebound and beat Rask through the legs.
The Bruins tied the game on Paille's fourth of the season at 12:06 as he sidestepped Erik Karlsson along the sideboards and beat Anderson.
Conacher made it 2-1 for the Senators at 14:28 when he tipped a Kyle Turris backhand.
The Senators made it 3-1 just 29 seconds into the second on Smith's short-handed goal. It also marked the end of Rask's night.
Anderson made several good saves through the second, but had no chance on Iginla's 12th of the season as he was left all alone at the side of the net for an easy tap in.
Warsofsky, with his first in the NHL, tied it 3-3 at 6:36 of the third with a shot from the side boards.
C Jason Spezza and D Chris Phillips missed the game with a lower-body injury. In Spezza and Phillips' absence Kyle Turris and Erik Karlsson wore an 'A'. D Eric Gryba was a healthy scratch for the Senators. ... The Bruins announced D Dennis Seidenberg will miss the remainder of the season with a knee injury. D Zdeno Chara was a late scratch and is listed day to day. The Bruins were also without C Carl Soderberg. D Zach Trotman was recalled on an emergency basis and made his NHL debut.
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OTTAWA, ON - DECEMBER 28: Clarke MacArthur #16 of the Ottawa Senators skates prior to an NHL game against the...