By Matt Kalman, CBS Boston

BOSTON (CBS) — The only numbers that really counted when the dust settled on Game 4 of the Eastern Conference first round on Thursday were 3 and 1.

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The Bruins defeated the Toronto Maple Leafs 3-1 to take a 3-1 series lead. Boston can close out the series at home in Game 5 on Saturday.

But there were other numbers on the postgame stat sheet that had to be disturbing from the Bruins’ perspective despite the crucial victory.

The Maple Leafs had 70 shot attempts. The Bruins blocked 27 shots. That’s not a recipe for getting a result similar to Game 4 when they play Game 5, and the Bruins will have to make serious adjustments in order to avoid letting Toronto get off the canvas and extend this series.

“I think you give up something. We gave up the ice in front of us instead of behind us,” coach Bruce Cassidy said Friday, explaining how his team limited the stretch passes but instead got hemmed in their own zone.

“So they have more O-zone time because they got pucks behind us, we had to break out a little more. That’s the give and take … we had to make sure that we took away one of their strengths, or tried to. We attempted to and I thought it worked for the most part. … We trust our D-zone coverage, I think we’re pretty good at it, we’re willing to block shots and I think for the most part we kept our Grade A chances [against] to a minimum.”

Let’s face it, the Bruins dodged a bullet in Game 4. Tuukka Rask made some sensational saves. And even if Cassidy’s right and the Grade A chances were limited, the Bruins were taking a big risk that Auston Matthews or William Nylander or one of Toronto’s other dynamic offensive talents wouldn’t finally make an electrifying play in the midst of all the Maple Leafs’ zone time.

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The 27 blocked shots weren’t a totally disgusting total. As center Sean Kuraly said, “when guys are willing to show that they’re going to sacrifice for the team like that, that’s a good sign.” But there’s a reason the Bruins ranked 30th in blocked shots with 1,072 during the regular season. They made sure all season to avoid running around in their own end by going on the attack, cutting off plays in the neutral zone or just inside the blue line, and letting Rask or Anton Khudobin handle the last-line-of-defense chores.

The Bruins can show all the courage they want in front of the Maple Leafs’ shots and pray Rask comes up big again in Game 5, but their odds of finishing this series will shrink significantly if they spend another three periods chasing the puck around the defensive zone.

An excessive amount of attacking-zone time for the Maple Leafs can lead to bad bounces that even Rask can’t stop. It can lead to exhaustion, especially for Boston’s best players. That not only could impact this series, if there’s more than one game left, but future series. And, of course, the longer the Maple Leafs are in Boston’s grill the better chance there is for Matthews or Nylander, who’ve combined for two points in four games, to get going either through a high-skill play or a lucky break. On a related note, that much defensive-zone time is bound to lead to more power plays against, another opportunity for Toronto’s high-end players to gain confidence and maybe begin to produce.

If Matthews & Co. are playing 180 feet from the Boston net, they can’t get going. And that means better support of the puck by the Bruins and better management of the puck from their own blue line to Toronto’s goal line.

“Well I think they do a great job of moving pucks quick and getting them deep,” said Bruins defenseman Adam McQuaid, who could benefit from less shot blocking after getting one off the throat in Game 3 and one off his hand in Game 4. “So obviously you try and have good breakouts and quick exits … and with that just being strong on the puck in the offensive zone and making smart, strong plays. I think that those are some keys.”

“Obviously they kind of had a little too much zone time last game. I think we just have to do a better job of puck management … maybe put the puck in situations where they’re not able to kind of stretch us out and get the puck up quite as quick,” Bruins defenseman Matt Grzelcyk said. “The best way of not playing defense is staying their zone and making them defend, so hopefully we get back in our own building and we can do a better job of that like we did in Games 1 and 2.”

If recognizing a problem is the first step toward fixing it, the Bruins seem to be headed in the right direction. The Bruins will take a series-clinching win any way they can get it, but they know in order to eliminate the desperate Maple Leafs, they’ll probably have to produce some handsome numbers more suitable for printing on the postgame stat sheet after Game 5 than they did in Game 4.

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Matt Kalman covers the Bruins for and also contributes to and several other media outlets. Follow him on Twitter @MattKalman.