By Michael Hurley, CBS Boston

BOSTON (CBS) — There may be no word more overused in sports than “pivotal.” Despite that, it’s almost always used to describe a Game 5, and it’s not often used for Game 4’s.

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That should not be the case, and the current Stanley Cup Final is the best example of that.

While past results don’t predict future events, historical data shows that the swing for the winner of Game 4 is about as significant as it gets.

In the history of the NHL, when a team has won Game 4 to take a 3-1 lead, that team has gone on to win in 220 of the 245 times it’s happened — an 89.8 percent rate of victory. When that team has done that as the road team in Game 4, the team has gone on to win the series 91.8 percent of the time (134 out of 146 occurrences).

So, historically speaking, if the Blues had lost Game 4, they would have joined that group that has won in such situations just 8.2 percent of the time. The Bruins would have been sitting pretty.

But that’s speaking in terms of all postseason series. In terms of the Cup Final? No team has ever rallied from a 3-1 series deficit (after losing Game 4) in the final series of the NHL season. Teams that have fallen behind 3-1 with a Game 4 loss are 0-for-27. (The 1942 Maple Leafs rallied from a 3-0 hole to win the Stanley Cup Final, the only team to ever rally from any 3-1 deficit in the Cup Final.)

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Again, other teams’ failure in that spot would not have necessarily doomed the Blues. But generally speaking, it’s ideal to avoid joining that company with 0 percent success.

And so, by winning Game 4, the Blues have knotted the series at two games apiece. Doing that has generally put things back at 50-50 in terms of the history of NHL playoff series.

Teams that have won Game 4 to tie the series at 2-2 have gone on to win the series 47.3 percent of the time. That success has dipped a bit when it comes to the home team winning Game 4, at 39.8 percent success in the series.

Still, the jump from having between 0 and 8 percent of history on your side to somewhere between 40 and 47 percent of history is incredibly significant. On the flip side, the Bruins went from this series victory being a near-certainty to a point where there’s now plenty of reason for doubt.

Moving in closer, looking specifically at the Cup Final, teams to win Game 4 to tie the series at 2-2 have ended up winning 10 out of 25 times — 40 percent. The 2013 Boston Bruins played a role in two such instances, winning Game 4 and the series in 2011, and losing Game 4 and the series in 2013.

Game 5, will of course, get the “pivotal” label from everyone who discusses the game. In Stanley Cup Final history, the winner of Game 5 to break a tie has gone on to win 18 out of 25 times (72 percent).

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The exact numbers hardly matter now. Really, what does matter is that the Blues have every bit of a chance to win this Stanley Cup as the Bruins do, and that is precisely what swung over the course of Game 4 on Monday night.