Tuukka Rask  picked up his league-leading fourth shutout of the season and Reilly Smith scored twice as the Bruins returned to action with a 5-0 win over the Senators Friday night at TD Garden.
After a sluggish first period, the Bruins got on the board with a power-play goal from Jarome Iginla. David Krejci  made it 2-0 on the opening shift of the third by beating Robin Lehner from a tough angle at the bottom of the right circle, with Smith making it 3-0 as he capped a rush with Brad Marchand . Smith scored his second of the night to give him a team-leading 14 goals on the season when he picked up a loose puck in the slot and beat Lehner. Marchand made it 5-0 with a shorthanded breakaway goal with 27 seconds remaining in the game.
Rask stopped all 33 shots he saw on the night.
The game marked Daniel Paille ‘s return to the lineup from a mild concussion. Paille, who had missed the last seven games, skated Friday on the fourth line with Gregory Campbell  and Jordan Caron in addition to taking his regular penalty-killing duties.
The Bruins will play the second game of a home-and home with the Senators Saturday night in Ottawa.
WHAT WENT RIGHT FOR THE BRUINS
– Smith now has seven goals over his last six games. He was absolutely not a throw-in in this summer’s trade, but he’s still performing better than anybody could have expected.
– Krejci has been a beast at TD Garden of late, notching four goals and seven assists for 11 points over his last eight home games.
– After years of struggling to produce on the power play, the Bruins have finally turned the man advantage into a source of offensive production — especially lately. Iginla’s goal was his second power-play goal in as many games and made for Boston’s fifth power-play goal in the last three games.
– The Bruins bounced back from a rough first period by coming out hard in the second. After getting outshot by a 15-5 margin in the first, the B’s outshot the Senators, 20-8, in the second period.
– With his second-period goal, Iginla now has three goals over his last two games and six goals over his last nine games. Iginla was playing well despite a lack of scoring early on in the season, but the goals are finally starting to come for the first-line right winger. He’s up to 11 on the season now, which is two behind Smith for the team lead.
– The Bruins caught a break in the second period when Jean-Gabriel Pageau negated a Smith high-sticking penalty by going after Smith and being sent off for roughing.
– Speaking of penalties, Patrice Bergeron  did not take a penalty for the first time in five games after a very uncharacteristic stretch that saw him total 15 penalty minutes over a four-game span.
WHAT WENT WRONG FOR THE BRUINS
– Dennis Seidenberg  left the game in pain with about four minutes to play and did not return. He got tangled up with Cory Conacher as the two went behind the Bruins’ net, and Conacher fell on Seidenberg’s right leg awkwardly, causing what appeared to be some right knee pain. Seidenberg held his right knee before getting off the ice slowly.
– The B’s managed just five shots on goal in the first period that saw them get a couple chances but fail to capitalize. Marchand hit the post on an odd-man rush with Smith, but the best opportunity came with about a minute and a half to go. After blocking a shot in the defensive zone, Marchand raced Lehner to a puck in the Ottawa zone and got to it before the Ottawa goalie. He tried to send the puck to the high slot with Lehner still out of his net, but the pass — which was loosely intended for either Smith or Bergeron — was intercepted by Jared Cowen and cleared.