The Capitals discuss their 3-1 win over the Rangers in the playoff opener. (Nick Plum for Synthesis/Koubaroulis LLC/The Washington Post)

Just more than three minutes into the second period of Thursday night’s playoff opener against the New York Rangers, the Washington Capitals took to the power play for the third time. “It’s playoff hockey,” forward Marcus Johansson said later. “There aren’t going to be too many chances.”

Yet here they came, one before the game was a minute old, another late in the first, another to open the second. And there, on that third chance, the Capitals struggled to even keep the puck in the offensive zone. With the Rangers already leading 1-0, the Verizon Center crowd collectively cringed when dangerous New York center Derek Stepan broke away for an oh-no-but-we’re-on-the-power-play chance.

“We needed to move forward with our PP,” Capitals forward Troy Brouwer said. “I think they had more chances on our PP than we did.”

The playoffs are only a game old, and it’s far too early to establish trends and themes. But consider the two divergent forces that were well-established long before Washington took a 3-1 victory to begin the series: The Capitals have the league’s best power play. And power plays are more difficult to come by as each postseason game goes by, as spring pushes further from winter.

“I’m not really too concerned about it,” Capitals Coach Adam Oates said.

Track every shot in the Capitals’ playoff games, see which ones they made count, and view by player, goals and ice strength.

He doesn’t need to be, because his team won its opener, because its last two power plays of the night looked crisp and because he knows a single game in what could be a long postseason haul doesn’t provide absolutes.

But consider how the Capitals got here, to being Southeast Division champions, to being favorites over the Rangers. In the 48 games of this lockout-shortened regular season, they scored 41 goals with a five-on-four advantage. Next highest: Philadelphia and Montreal, each with 35 — a huge gap. That represented 28.1 percent of the Capitals’ offensive output in the regular season, the highest percentage in the NHL.

So by almost any measure — efficiency rate, gross number of goals — the Capitals’ power play was lethal. But they also rely on it more than most teams. “It’s huge,” Johansson said.

The Rangers, though, enter this series as the least-penalized team in the league. So mix all that together: one team that wants and needs to score on the power play — and is superb at doing so — against a team that rarely takes penalties, competing in an environment in which penalties are less likely to be called. It made that discombobulated power play early in the second period seem weighty.

“Maybe a little jitters,” Oates said.

Those should be long out of the way by Saturday’s Game 2. But there the Capitals were — up a man, down a goal and feeling the pressure to play to their strength.

“First power plays . . . I think we feel like a little bit, maybe, nervous,” star winger Alex Ovechkin said.

It is the Rangers, though, who should be nervous about their time in the box — both Thursday night and going forward. They have a reputation for laying out and blocking shots, for doing the kinds of things that negate the man advantage. But they finished the regular season as a middling penalty-killing team, 15th in a 30-team league. And when Arron Asham was called for an illegal check to the head just 72 seconds after the Rangers had killed off their third penalty, there was a sense of foreboding on the New York bench, as there might be for the rest of the series.

“You can’t take two in a row,” Rangers Coach John Tortorella said.

That shift helped change the game. Had the Rangers killed off that penalty, too, their lead would have been intact, and the Capitals might well have questioned what has been their greatest strength. But defenseman Mike Green, who missed 13 games because of injury but still managed 14 power-play points, fired a shot from the perimeter, only to bank it off the boards and right onto the stick of the net-crashing Ovechkin.

“Lucky bounce,” Ovechkin said. Sure, but this is what makes the Capitals’ power play such a potentially decisive factor in this — or any — series: If the Capitals get a lucky bounce, they’ll likely bury it. Ovechkin led the league with 32 goals in the regular season; 16 came on the power play. No other player had more than 10 power-play goals.

When Ovechkin shoved that puck past Rangers goaltender Henrik Lundqvist, Verizon Center burst, the score was tied and the Capitals could exhale — and cruise to a win. Their season-long strength was, for the moment, a strength again.

“We just have to make it simple,” Ovechkin said, “and it’s gonna work.”

Washington finished the night 1 for 5 on the power play, lower than its league-leading 26.8 percent success rate. But the tenor was established for Saturday and beyond.

“We can’t take that many penalties,” Tortorella said. He knows too well the potential costs of doing so. Nerves are now gone. The series is under way. And with every whistle, the Capitals’ power play lurks, ready to change the playoffs.