Updated

Claude Julien wasn't happy that his Bruins allowed 47 shots on goal. Fortunately for Boston's coach, his team took a season-high 50.

And their 46th, Nathan Horton's tiebreaking goal midway through the third period, gave them a 3-2 win over the Ottawa Senators with an uncommonly aggressive attack Tuesday night.

"It was good to see our team offensively create some chances because that's an area where we struggled," Julien said, but "I thought that we were very soft defensively."

The Bruins didn't wait for five-time NHL scoring leader Jaromir Jagr to show up to improve their offense. Hours after obtaining him from the Dallas Stars, the Bruins shook off their recent offensive woes with their second straight win after losing five of their previous seven games.

"There's no doubt he's going to help us," Julien said. "He's coming to help us. He's not coming to save us and that's what people have to understand. He's a great player. He still is a great player."

At 41, Jagr is far past his peak but still should help the Bruins' weak power play and add to their overall offense.

They had enough on Tuesday without him.

"We wanted to put pucks on net," said Tyler Seguin, who did that 12 times. "We knew they were such a defensive team so we wanted to come out pretty hard."

Horton got his 12th goal of the season at 10:21 of the third period after goalie Robin Lehner stopped Milan Lucic's shot with his pad. But Horton scored on the rebound.

Earlier Tuesday, the Bruins obtained Jagr for prospects Lane MacDermid and Cody Payne, both forwards, and a conditional second-round pick in this year's draft that becomes a first-rounder if the Bruins reach the Eastern Conference finals.

Jagr is expected to join the Bruins in time for Thursday night's home game against New Jersey.

The Bruins' previous season high for shots was 46 on Feb. 28, also against the Senators, in a 2-1 overtime win. Boston is 4-0 against Ottawa this season with every win coming by just one goal.

"That's the frustrating part for us," Senators coach Paul MacLean said. "We responded well after being down 2-1. We get the thing tied up. But when it's all said and done, they got one more than we did. Again."

The Bruins outshot the Senators 21-19 in the first period, their most shots in a period since they had 22 on Feb. 19, 2012, at Minnesota.

"Both teams did a lot of good things offensively," Ottawa's Daniel Alfredsson said, "but were sloppy with the puck. There were a lot of turnovers from both sides."

The pace slowed for a while in the third period after Andre Benoit tied the score 2-2 with 1:55 gone following an officials' review. Play had continued after Benoit's hard, high shot. At the next whistle, officials ruled that the puck had gone in just under the crossbar then come out, resulting in Benoit's third goal of the season.

"I wasn't happy with that," Bruins goalie Anton Khudobin said, "but, still, it doesn't matter. We got the W."

Colin Greening had given Ottawa a 1-0 lead 2:48 into the game before goals by David Krejci and Seguin 1:01 apart put Boston ahead 2-1 at 4:29 of the first period.

The game was "way too wide open for us" in the first period, Senators forward Erik Condra said. "After that it was a good game both ways. We struggled in the first and just never got it back."

Greening started the scoring on Tuesday when he took a loose puck in the slot and backhanded it between goalie Khudobin's legs. It was Greening's seventh goal of the season and third in four games.

But less than two minutes later, Boston had the lead.

Just 30 seconds after Greening's goal, Krejci got his ninth for the Bruins when he deflected Zdeno Chara's shot from the blue line past Lehner.

And 61 seconds after Krejci scored, Seguin gave Boston a 2-1 lead with his 12th goal of the season but only his second in eight games. Brad Marchand passed the puck across the slot from the left side and Seguin put it in the right side of the net that Lehner had left open when he skated toward Marchand.

Chara put the puck in the net for Boston at 12:11 of the first period, but the goal was waved off because Patrice Bergeron was in the crease.

NOTES: The Bruins scored in the first period for the first time in eight games. ... Bergeron, Boston's leading scorer, did not return after being hit in the head with Greening's elbow in the second period. Julien said he had no update on his condition. ... Rich Peverley took his place as the center between Marchand and Seguin. ... The game began a season-high seven-game road trip for the Senators. ... The Bruins are 22-1-0 when allowing two or fewer goals