OTTAWA — The Ottawa Senators got a preview of a potential playoff opponent — and liked what they saw.

Mike Hoffman had the power-play winner early in the third period as the Ottawa Senators defeated the Boston Bruins 4-2 on Monday night. The win allowed the Senators, who sit second in the Atlantic Division, to take a four-point lead on the third-place Bruins and still hold two games in hand.

"That was one of the toughest games we've played all year," said Hoffman. "For the whole 60 minutes we had to be sharp, we had to be on our toes. I thought everyone played sharp."

Derick Brassard, Jean-Gabriel Pageau and Alex Burrows, with an empty-net goal, also scored as the Senators (36-22-6) extended their winning streak to three games. Craig Anderson made 25 saves against the Bruins, who Ottawa will play twice more in the regular season.

Patrice Bergeron and Brad Marchand scored for Boston (34-25-6) as Tuukka Rask made 25 saves.

The Bruins anticipated a hard fought game, but struggled against the Senators forecheck.

"They played their game better than we played ours in a nutshell," said Boston coach Bruce Cassidy. "It was a little disappointing at times that we were that stubborn."

With just six remaining home games, the Senators gave the 17,046 at Canadian Tire Centre something to remember in what could be a preview of a first round playoff match-up should the standings remain as they are.

Ottawa took a 3-1 lead early in the third as Hoffman scored his 20th on the power play. It was Ottawa's first goal with the man advantage in three games.

The lead was short lived as less than two minutes later the Bruins scored on the power play as Marchand picked up a David Pastrnak rebound to score his 30th, giving him back-to-back 30-goal seasons.

Shortly after there was a strange turn of events in the third when it appeared Hoffman was going to take a slashing penalty, but then the officials overturned the call after realizing Marchand's stick had broken in the act of shooting.

Cassidy had never seen anything like it and was still confused by it after the game.

"It was a funny call. Through the course of the game most officials would tell you there's times they look back and tell you that was one I probably missed, but they don't tell you until after the game or the next day so again it was interesting to say the least."

There were no goals in the second, but the Senators clearly held the edge in the period, outshooting the Bruins 16-5.

"We played a complete game against a team that's played very well," said Dion Phaneuf, who wasn't expected to play as he wasn't feeling well at the morning skate. "It feels good when you come in and compete the way that we did together. We come out with the result that we wanted in a race that's tight."

Ottawa had a number of chances as the Bruins turned the puck over several times, but Rask was solid and got a little help when Phaneuf rang a shot off the post.

"We knew it was going to be a hard game and we definitely didn't have the start we would have liked," said Marchand. "We kind of played into their system. We didn't get enough pucks in deep and that's the game you have to play against this team wit the five guys in the neutral zone they really clog it up so we have to get in a little bit more than we did and hopefully we can do a little bit better next game."

The Senators had a strong start to the game as they held a 2-1 lead after 20 minutes.

"I thought we came out real focused, real strong," said Senators coach Guy Boucher. "When they got that goal we had a great push back."

Trailing 2-0, the Bruins cut the lead in half as Bergeron took a pass from Torey Krug in the slot and quickly turned and beat Anderson with a wrist shot in the final minutes of the period.

Brassard opened the scoring at 1:21 as he managed to beat Rask with a turnaround shot through traffic and Ottawa took a 2-0 lead just three minutes into the game as Pageau redirected Phaneuf's point shot.

The Senators now hold a 2-0 series lead as the two teams meet again March 21 and April 6.

Notes: Ottawa D Fredrik Claesson, D Jyrki Jokipakka and C Christopher DiDomenico were a healthy scratch. The Senators remain without Bobby Ryan and Chris Neil, who both have broken fingers. The Bruins RW Jimmy Hayes, D John-Michael Liles, D Joe Morrow and LW Matt Meleskey were a healthy scratch. Adam McQuaid was back in the lineup Monday. The Bruins defenceman needed over 20 stitches Saturday after taking a skate blade to the neck.