OTTAWA — The Boston Bruins were unable to record a single shot on goal in the second period Wednesday night, but they took the only two that mattered in the third.

The result was a 2-1 victory over the Ottawa Senators at Canadian Tire Centre that gives the Bruins a 1-0 lead in the best-of-seven playoff series between teams that finished three points apart in the Atlantic Division standings.

Frank Vatrano scored at 4:05 and Brad Marchand netted the winner with 2:33 left as the Bruins erased a lead Bobby Ryan provided the Senators when they outshot their opponents 12-0 in the middle 20 minutes.

“We didn’t have a good second, but we really did a good job of responding in the third,” said Marchand, who led the Bruins with 39 goals during the regular season. “That’s what you need in the playoffs. You need to be able to battle through that adversity.

“They’re a great team. They played a really good game tonight. We didn’t have a whole lot. We were lucky to win that one.”

Tuukka Rask was exceptional in goal for the Bruins, stopping 26 shots. Craig Anderson made 23 saves for Ottawa.

The Senators were guilty of multiple turnovers in their own zone just before Marchand scored.

“On both goals, we had the puck on our stick multiple times to get the puck out, and we just couldn’t do it,” said Anderson. “They made us pay. They’ve got good players and they made good plays. Little bit of a lucky bounce on the second one, it goes right to the guy, but it starts with making good decisions with the puck.

“Give them some credit. Tuukka played well in the second. Kept it at one goal and gave them a chance to win. That’s the goalie’s job. Tip your hat to him, he had a great second period.”

Already without injured defensemen Torey Krug and Brando Carlo, the Bruins lost Colin Miller on a second period hit by Mark Borowiecki. There was no post game update on Miller.

Stepping up with a big game was 40-year old blue liner Zdeno Chara, who led all player in ice time at 25:32 and topped Boston shooters with five. Also turning in an exceptional effort was 19-year old Charlie McAvoy, who was second on the Bruins in ice time with 24:11 in his NHL debut.

“I thought he was terrific,” said Boston coach Bruce Cassidy. “A 19-year-old kid comes in, never played a game in the NHL, had composure, saw the ice, defended well. Losing Colin Miller sort of magnifies the situation. If he had struggled, we would have really been in trouble, so it was a nice boost for us.”

Ryan’s goal was on a spectacular solo effort, as he burst into the Bruins zone, bumped Adam McQuaid off the puck, cut through the slot between Rask and Chara then fired it in from a sharp angle.

Ryan led the Senators in shots with six, but all of them were in the first two periods. Ottawa was guilty of trying to protect the lead in and was outshot 11-6 in the third.

“We sat back a little bit,” said Ryan. “We had some turnovers in our end and it gave them zone time. They outplayed us when it counted in the third period.

“But at the same time, there’s a lot of positives. We held them to without a shot for quite a bit of time. We had a lot of chances. We’re going to have to find a way to score more than one to win, going forward.”

Erik Karlsson said the Senators were guilty of getting “too cute” when they should have put the Bruins away.

“I didn’t like our shooting mentality in the third period, that’s for sure,” said coach Guy Boucher. “That’s where I think we were too cute. If you don’t have a shooting mentality against a good goalie like Rask, and he sees all the pucks and there’s not a lot of them, you’re probably not going to score any.

“But having said that, what lost us the game is not that we didn’t score another one. It’s that we gave two, where normally we don’t do those mistakes. At 1-0, we should have been able to close that game like we normally do. They took advantage of it.”

The Bruins playoff experience played a part in their rally.

“There were a few things said (between the second and third) but the gist of it was we were calm in there,” said Cassidy. “The message was more about this wasn’t Game 83, this was Game 1 of the Stanley Cup playoffs. The urgency level goes up, the physicality goes up, doing the little things, winning pucks. We just had to get back to our standard we had played to the last two months.

“We didn’t seem to be able to win enough pucks, whether we were nervous, not invested enough, waiting to see how things would play out, whatever the case was, and as a group we had to start winning more pucks. We addressed that first and foremost.”

NOTES: Bruins C David Krejci, a two-time winner of the NHL playoff scoring race, was a late scratch … Other injured Bruins included D Torey Krug and D Brandon Carlo, neither of whom accompanied the team to Ottawa, and C Noel Acciari … Bruins scratches were RW Jimmy Hayes, C Jakob Forsbacka Karlsson and D Joe Morrow … Senators D Marc Methot took the pre-game warmup but did not play. Methot has been out since having the tip of a finger severed by a Sidney Crosby slash on Mar. 23 … D Fredrik Claesson took Methot’s spot in the lineup …Other significant Senators scratches were LW Ryan Dzingel, C Chris Kelly, RW Chris Neil, D Ben Harpur and C Colin White.