The Boston Bruins advantage in the depth department really came to the fore in their thrilling 5-4 comeback win in overtime against the Canadiens on Thursday night.

When you get three goals from your third line, including the tying and winning goals, it shows to what extent the Bruins can rely on contributions from a larger group of forwards than the Canadiens.

Except an interesting development in the series unfolded over the course of Game 4, one that could play a determining role in the Canadiens chances in Game 5.

David Desharnais, somewhat out of the blue, became an extremely important player.

Before the game, Desharnais was asked why he thought he was having trouble keeping up with the pace of the playoffs, and he chalked it up to the same tentativeness he showed when he was first called up from Hamilton.

But he also said he was starting to get the hang of it, and predicted a better performance in Game 4.

He's hardly the first struggling player to say that, but Desharnais also delivered on his promise.

Who can forget Desharnais going after a puck along the boards behind the Boston net against big Zdeno Chara, disappearing for a while, then coming out with it during a first period penalty kill? I made a request on Twitter after that play for someone to write a joke about the situation, and the winner was "David and Zdeniath." That inspired @SoftEuropean, a Habs blogger in France, to submit this quick Photoshop gem.

It was a perfect illustration of the kind of effort Desharnais put in all night.

"It was probably the best playoff game I've seen David play, he had a lot of energy, a lot of jump right from the first period," Jacques Martin said Friday. "As the game went on, especially in the third period, he played against a pretty strong opponent and did a good job."

That opponent would be Patrice Bergeron, who spent almost the entire first 40 minutes playing against Scott Gomez's line and had a veritable field day. Through two periods, Bergeron had a goal and an assist, seven shots on goal and was 10-6 in the faceoff circle, 8-5 against Gomez.

Just after the six-minute mark of the third period, with the Canadiens up 4-3 and a faceoff coming in the defensive zone, Martin kept Lars Eller, Ryan White and Tom Pyatt out against Bergeron's line. Predictably, Bergeron won the draw and the Bruins proceeded to go on a wild scramble to try a tie the game, one that included four shots on Carey Price, the final one being Johnny Boychuk's attempt that landed in the trapper of the sprawled out Canadiens goalie.

Eller and White never played another shift.

From that point in the game onward, Desharnais, Pyatt and Jeff Halpern were assigned the task of stopping Bergeron. On Bergeron's final five even strength shifts of regulation time, that was the match-up, and over that span his line did not get a single shot on goal and only attempted two. Desharnais also won three of six faceoffs against Bergeron, which is no small feat considering Gomez and Tomas Plekanec won a combined six faceoffs against him in 17 tries.

It will be interesting to see if Claude Julien tries to get Bergeron back on the match-up with Gomez in Game 5, and also if Martin will keep the combination of Desharnais, Halpern and Pyatt as a defensive line.

Because depth is not all about scoring. When you have a line who can keep it away from your own net as effectively as those three did in the third period, it can be just as valuable.