Karl Alzner, left, and Nicklas Backstrom helped the Capitals elude the Flyers to earn the Eastern Conference’s top seed. Now a first-round matchup with the Rangers awaits. (Toni L. Sandys/WASHINGTON POST)

Four months ago, the Washington Capitals fell silent at Madison Square Garden and surrendered their worst loss of the Bruce Boudreau era, 7-0, to the New York Rangers. The defeat, which came in the middle of an eventual eight-game losing streak, prompted the shift to a more defensive system and mind-set.

When the Stanley Cup playoffs open this week, the Capitals will meet New York in an Eastern Conference quarterfinal series as the fully evolved team that found its identity after that ugly night in December.

The Capitals did not have much regular season success against the Rangers, who clinched the eighth and final playoff berth in the East on Saturday. In four games between the two clubs, Washington went 1-2-1 while being outscored 17-6 in a set of contests that included two shutouts — the 7-0 drubbing on Dec. 12 and a 6-0 loss on Feb. 25.

The Capitals believe they are a different team now, though.

“It’s completely different. They got us in the middle of our transition to the game we’re playing now,” defenseman Karl Alzner said. “Not taking anything away from [the Rangers]; they played great hockey against us and we just couldn’t hang with them at that time. Hopefully it’s going to be a different story now.”

While the Capitals have been integrating more of a defensively sound approach to their game plan this season, the Rangers have long built their foundation upon reliability in their own zone. As they kick off the best-of-seven series Wednesday night at Verizon Center, the two teams are more similar than they might have been at the start of the year.

New York finished with 1,301 blocked shots — fourth most in the NHL — a number that speaks to a willingness to protect their end at all costs. Coupled with the steadiness of all-star goaltender Henrik Lundqvist, the Rangers have the fifth-best goals against average per game at 2.38.

Lundqvist is the type of netminder who has the ability to alter the outcome of a game or even a series. Over the course of his career he has gone 14-10-2 against Washington, with a .906 save percentage and 2.81 goals-against average, including postseason action in 2009. The Capitals rallied from a 3-1 deficit to win that series in seven games.

“I don’t think you can ever learn how to beat that guy,” winger Matt Bradley said. “When he’s hot, he’s tremendous in net. We have a lot of guys up front that can score and on defense, so I think if we play our game the proper way then we’ll get our goals.”

At the conclusion of the regular season, the Capitals boasted the fourth-lowest goals against average, at 2.33 goals per game, and have 1,257 blocked shots (seventh), led by five defensemen who have more than 100 blocks each. In the final 20 games, Washington allowed only 37 goals for an average of 1.85.

The Rangers say they aren’t naive enough to believe that simply because they defeated the Capitals in the regular season, it will be an easy task to do the same in the playoffs.

“I’ve been on teams that have done well in the series and lost in the playoffs, and vice versa,” New York captain Chris Drury told reporters on a conference call. “To me, it’s a whole new season and something we can learn from, having played against them and had success in the year. Ultimately, it is a totally different season, different animal, and the last few weeks we know they’ve done different things to have success. We’re going to have to be ready, no matter what happened in the regular season.”

To counter a team with the same philosophies, the Capitals understand they will need the attention to detail. From dumping pucks in deep in the Rangers’ zone to crashing the net and making sure to get clean clearing attempts out of their own end, every little factor could shift the momentum. Then there’s the physical element that comes naturally, considering the Capitals and New York are well-acquainted after regular season contests and the first-round playoff meeting in 2009.

That familiarity may lead to a little more animosity, but the Capitals have bigger goals in mind than exacting revenge.

“They had a lot of luck against us during the regular season. We’re both different teams now, and that was a while ago,” winger Mike Knuble said. “Our only redemption is for ourselves and for our group and trying to be better than we were last year. That’s the biggest motivator we have.”