If nothing else, this game showed that it will not be over in five games like some are predicting.
The entire game was a war of attrition and it took overtime to decide the outcome. This means that with a win on Saturday, each team's prospects of advancing will be drastically improved.
If the Bruins win, then Washington will have to win four of the next five. That's certainly not impossible, as they have done that before, but it's not very likely.
If the Capitals win, however, they'll be going back to Washington with the series dead even. That plays right into their favor and if this series becomes a best-of-five, then anything can happen.
Simply put, the Bruins need a win to give themselves significant breathing room, and the Capitals need a win to give themselves a legitimate chance at winning the series.