NHL

Playoffs open with Rangers needing to play disciplined

WASHINGTON — Let us break down this Rangers-Capitals first-round playoff series that begins here tonight to its most fundamental equation.

The Blueshirts had the third-best five-on-five goal ratio in the NHL at 1.30 during the regular season, eclipsed only by prohibitive conference favorites Chicago (1.52) and Pittsburgh (1.35).

The Caps, meanwhile, were 10th at 1.07.

The Rangers were a middling penalty-kill team overall, 15th in the league at 81.1 percent, and feeble on the road, fifth-worst in the NHL at 75 percent.

While Washington had the NHL’s most potent power play at 26.8 percent overall while second-best at home at 27.2 percent.

All of which adds up to this essential truth as communicated yesterday by Derek Stepan, who teams with Ryan Callahan on the Rangers’ top penalty-kill unit: “The best kill is not to be in the box.”

“We have to do our best to stay disciplined and not get ourselves in trouble,” Stepan said. “We’re aware of that.”

Or, as Callahan said, “It’s no secret how dangerous their power play is. Staying out of the box is definitely one of the keys for us.”

RANGERS PLAYOFF SCHEDULE

This marks the third straight year and fourth in the last five tournaments in which the Blueshirts and Caps have met, the Rangers’ seven-game victory in the conference semifinals last year following first-round defeats in seven games in 2009 and in five games in 2011.

Indeed, after taking the opening two games of the 2009 series, the Rangers and Henrik Lundqvist have lost seven of the last eight playoff games in D.C., the only victory last year’s Game 3 triple OT classic.

“That doesn’t mean anything,” Callahan said. “It’s a matter of playing a good road game. We know they’re going to come with a lot of energy the first 10 or 15 minutes, so we have to be ready for that.

“We’ve been in playoff-style games for the last three weeks, and that’s when we’ve been at our best. We have to take that energy level and raise it a notch.”

Coach John Tortorella hasn’t said whether he’ll keep his shutdown defense pair of Ryan McDonagh and Dan Girardi intact to match against Alex Ovechkin, but chances are better that the Blueshirts will stand if the tandem is united and fall if it is divided; at least as long as Marc Staal remains sidelined.

Staal clearly was uncomfortable responding to the direct question put to him yesterday about whether he had ruled himself out for Game 1, the alternate captain all too aware of the coach’s “loose lips sinking ships” philosophy.

But the defenseman did say, “I’m probably not going to play. As I’ve said before, I have good days and bad days, and I’ll keep taking it day by day and hopefully it will get better.”

The Rangers scored two goals or fewer in 13 of their 20 games in last year’s playoffs, getting to four in only Game 1 of the first round against Ottawa. That was the primary motivation in trading for Rick Nash, whom management perceived as the missing link.

“It’s a deal you do 10 times over if you get the chance,” Tortorella said of the exchange in which Brandon Dubinsky, Artem Anisimov, Tim Erixon and a first-round pick went to Columbus. “You just don’t get that kind of player.”

Nash has won a Gold Medal for Canada in the Olympics and World Championships, but never has played in so much as a winning game in the NHL playoffs, his Jackets swept in four by the Red Wings in 2009 in his only previous trip to the tournament.

No. 61 is a multi-dimensional player, but he needs to score in this tournament and he needs to score in this series.

“It’s time to step up now,” Nash said. “There are no other options. That’s the way it has to go.”

That, and the Rangers staying out of the penalty box.