BOSTON – When the Bruins look in the mirror, they see the Blackhawks. Or, when they look at the Blackhawks, they see themselves.

Game 3 of the Stanley Cup Finals Monday night at TD Garden, saw the Bruins win 2-0, and wrest a 2-1 lead in the series. 

The Bruins were skating on home ice for the first time since June 7 when they eliminated the Penguins in a shocking four-game sweep.

The Bruins and Blackhawks could not have been more evenly matched through the first two games of this series. 

That’s why it took 10 periods to play those two games. Through three hours, five minutes, and 56 seconds of playing time each team had scored five goals. The Blackhawks were scoreless on six power-play opportunities, while the Bruins had one power-play goal in five chances.

Both goalies have been terrific. Tuukka Rask, putting together the best playoff run by an NHL goalie this side of Tim Thomas’ ranch in Colorado, has been the Bruins’ best player since the regular season ended. It was Rask — and pretty much only Rask — who kept Chicago from blowing out the Bruins in Game 2 Saturday night, not to mention Monday night’s Game 3 blanking.

Whatever Claude Julien said in the dressing room during that Game 2 intermission has worked. The Bruins limited the Blackhawks to just nine shots through the rest of regulation.

Motivating a team is one thing. Making adjustments that will change the performance of a team is another. Julien changed the combinations of his third and fourth lines, and it was the third line that scored the game-tying and game-winning goals.

Chris Kelly got the Bruins on the board in the second period with his first goal of the playoffs. Daniel Paille ended the game in OT with his third.  Assisting on each of the goals was Tyler Seguin.

It’s funny to think of Seguin as anything other than a top-six forward. Yet that’s what he is on this deep Bruins team. Seguin’s time as a top-line skater will come. For now, Kelly and Paille were happy to be skating with him.

After Game 2, Kelly was asked about the production of the “bottom six” forwards. Kelly chuckled at the concept of being a “bottom” player, but gave a serious answer:

“I know the ‘bottom six’ haven’t been there for that much for the playoffs in scoring, but we’re trying to do our best,” said Kelly.

“We were able to come up big, and for Claude (Julien) to kind of put a guy and have him stick in there, it definitely makes us feel comfortable and confident and good about our game. We were just happy to make him look good.”

With these two teams so closely matched, it’s easy to imagine the top lines cancelling each other out as we go deeper into this battle. Depth is paramount, and the team that gets contributions from top to bottom is most likely to come out on top.

“You look at the last game when they won, their heroes were guys from third, fourth lines,” said Julien. “Same thing for us. That’s why you need depth in the playoffs. Top lines are playing head-to-head, top D. It’s not always that easy to score.”

We’ve seen that it definitely is not going to be easy to score. Coming home down two games to none would’ve made for an unenviable task. In a game that “only” lasted four periods, the Bruins were the deeper team.

And that depth is the biggest reason the Bruins now hold a 2-1 advantage with Game 4 Wednesday night.

Tom Caron is the studio host for Red Sox broadcasts on the New England Sports Network. His column appears in the Press Herald on Tuesdays.