NEW YORK — The Washington Capitals’ boy-goalie Braden Holtby wheeled back and forth as the New York Rangers pecked and jabbed at him. They circled him like carnivorous bats, testing his nerves, his orientation, and his peripheral vision. All of those held up fine. What lapsed was his concentration. It only took 90 seconds — one small break in his attention span — a minute and a half in which he looked less like a staunch NHL netminder than a kid chasing butterflies.

That was all the Rangers needed early in the third period to turn a 1-1 tie into a one-game lead in the Eastern Conference semifinals. Only 90 seconds. That was the difference in this grudging, stubbornly obstructionist game between two seven-game survivors from the previous round. It came down to the goaltenders; as everyone knew it would. Looming in the net for the Rangers was the impassable Henrik Lundqvist, the 30-year-old Swede who’d choked off the Ottawa Senators by holding them to two or fewer goals in five of seven games. Standing behind him was a capacity crowd issuing a roar that felt like a force field, “Hen-REEK! Hen-REEK!” While on the other end of the ice was the doe-eyed Holtby, the 22-year-old who had been so preternaturally reliable for the Capitals in seven games against the Boston Bruins. But who surely had to crack sometime. Didn’t he?

Both were defensive-minded teams that knew each other too well and it made for ugly if taut action. For much of the game, trying to score was like trying to shoot the puck through a chain link fence. There was always an obstacle in the way, a stick, a skate, an arm or a leg. The Capitals squandered a five-on-three power play. Alex Ovechkin was held without a single attempt on goal through two periods. Both offenses at times looked like they were skating with shovels instead of sticks. The Rangers got off just 14 shots on goal, the Capitals 18. There wasn’t a lot for a goalie to do. “It was a tough game, mentally wise,” Holtby said.

The crucial difference: the Rangers made three of theirs count. In those fleeting 90 seconds, for the first time, Holtby looked overwhelmed. It was like a wave of tension had been building, and it finally broke over his head.

A game that had been slow and plodding suddenly turned fast — too fast, at the seven-minute mark of the third period. Rookie Chris Kreider look advantage of a bad line change and ripped a slap shot that streaked past Holtby’s glove. It was an inexcusable lapse from that range, and Holtby knew it. “The release of the shot kind of fooled me,” he said. “It was a nice placed shot. But from that range I’d like to have it back.”

Holtby flipped off his mask to reveal his smooth beard and took a long drink. He tried to act nonchalant and collect himself, remind himself that, “if they come down and score it’s not the end of the world.” But he was vulnerable, and the Rangers seemed to know it, and they came at him again, wheeling around like gulls.

At 8:30 of the third period, this time it was Brad Richards who took a chipped pass from Kreider, pinned to the left wall. Richards glided toward Holtby with an almost casually predatory air. He idled to within a few feet of him — almost toying with the kid — and then slid the puck right between Holtby’s pads.

It was a case of sheer youth, and there was nothing Holtby could do about it, except learn. Afterward, Holtby would admit that he simply had lost his focus. With just a 72-hour turnaround after beating the Bruins in Game 7, he had trouble gearing up again. The victory against the defending Stanley Cup champions seasoned him and gave him all kinds of confidence — but it also perhaps left him mentally drained. The veteran Lundqvist, though, had just a 48-hour span between contests.

“I had a tough time getting into the game,” Holtby said. “I didn’t bring my level up when I needed to. I have to keep my mind in it.”

It was probably inevitable that Holtby would suffer some sort of mini-collapse like this. He was playing in only his 29th NHL game ever, in the dark roaring pit that is Madison Square Garden. All things considered, the Caps couldn’t be too unhappy with his performance. “He gave us a chance to win and that’s all you can ask for in a goaltender,” coach Dale Hunter said.

The trick for Holtby now is to recover his equilibrium and concentration, and remember that it’s a best-of-seven series. As Brooks Laich put it, “They didn’t win all four games tonight.” This is a Rangers team that loves nothing better than a protracted defensive stalemate. “It’s gonna be a grinder,” Rangers Coach John Tortorella promised.

We know Holtby is a phenom. Now he has to learn to grind.

For Sally Jenkins’s previous columns, see washingtonpost.com/jenkins