It was one of the more thrilling games of the postseason so far, filled with big hits, scoring chances and, more than anything, great goaltending from Tuukka Rask and Carey Price.

And at the end of the night, there was just one goal up on the board, as the Boston Bruins took Game 4 1-0 courtesy of rookie Matt Fraser's overtime tally, tying their series with the Montreal Canadiens.

Goals in general have been hard to come by of late in the playoffs. After a wild first round filled with two- and three-goal comebacks and 282 goals in 48 games (5.88 goals per game), the second round has seen that average drop by more than a goal a game (4.86) so far.

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Generally speaking, that's how the NHL playoffs tend to play out. The first round begins with a lot of scoring and excitement, and then it tapers off after the first five or six games in each of those early series.

The final 20 games of the postseason – basically Round 3 and the finals – then usually average well under five goals a game.

Here's an illustration of that based on the last two postseasons (2012 and 2013), using 10-game rolling averages for goals scored per game:

Why this happens can be tracked back to a couple of things, but the biggest single difference between the regular season and the playoffs in the NHL actually comes down to simple save percentages.

The last two years, for example, save percentage has jumped from .910 to .920 in the playoffs, and it progresses higher deeper into the postseason.

Some of that is the fact more penalties are called in the opening round, but even if we look solely at even strength play, save percentage goes up remarkably from the regular season. On average, the last two years, goaltenders have improved from .921 at even strength during the season to .932 in the playoffs, which is the very peak of elite goaltending performance.

Where you can really see that is in looking at how similar the number of shots on goal, shot attempts and even the amount of time spent on the power play are between the regular season and the playoffs:

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All situations Season Playoffs Minutes per game 60.9 63.5 Goals per game 2.66 2.47 Shot attempts per game 55.2 58.8 Shots per game 29.4 30.7 Shooting percentage 9.0% 8.0% Save percentage 0.910 0.920 Even strength Season Playoffs Minutes per game 49.4 50.7 Goals per game 1.87 1.66 Shot attempts per game 44.5 46.6 Shots per game 23.8 24.3 Shooting percentage 7.9% 6.8% Save percentage 0.921 0.932 Special teams (PP) Season Playoffs Minutes per game 5.39 5.90 Goals per game 0.58 0.60 Shot attempts per game 8.4 9.7 Shots per game 4.4 5.0 Shooting percentage 13.0% 11.9% Save percentage 0.870 0.881

Common wisdom when it comes to the NHL playoffs is that they are lower scoring than the regular season for two key reasons: (a) the officials put the whistle away and (b) teams play tighter defensive systems.

Statistically speaking, however, that doesn't appear to be the case, and the goalies are making the biggest impact.

Teams have actually had more power play time in the postseason than the regular season in most recent years, and with overtime factored in, they are also generating more opportunities to score.

If you think about it, too, it makes sense that the biggest difference overall is better goaltending. The playoffs generally mean that backups no longer play at all, and it's usually only No. 1 goaltenders on a hot streak that tend to progress through the rounds.

The average even strength save percentage during the season may have been down at .921, but the average when you remove all play by backups was actually closer to .924.

Take out the starting goalies on teams that missed the playoffs and that rises up to .927.

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Save percentage also tends to increase as the playoffs wear on (as shown in the graph at the bottom), which is what we're seeing now with the goaltending duels like the one between Rask and Price, two of the top four starters in the league.

A much higher percentage of the games late in the playoffs are simply between teams with great goalies, and that, more than anything, is what's dragging down that goals per game average.

That's why the games are still exciting, even without the goals: All that's really changed is it has become a best on best battle, at every position.

Including the most important one.

