He was all alone at this precious moment, whirling his fist and beckoning the Washington Capitals to join in, showered in a din of his own creation. Three New York Islanders watched from afar, white-dressed monuments frozen by the rookie forward’s brilliance. Evgeny Kuznetsov had blurred through them and danced around them, the puck dangling from his stick, history and demons and magic carried with it. He had spun his hips, looked toward the net and waited for an opening. He would end so much torture with one flick of the wrist.

“It was unbelievable,” he said. “If you’ve never played the hockey, you’ve never feel this. I don’t know how to say. I’m so excited.”

The embers of the Capitals’ season glowed anew when Kuznetsov whipped the decisive goal with less than eight minutes left in Monday night’s 2-1 victory, and burned even brighter when his teammates snuffed defenseman John Carlson’s roughing penalty in the dying moments. As Verizon Center thundered and their postgame scrum knocked the net off its moorings, the Capitals had survived another Game 7. They had advanced to the Eastern Conference semifinals to face the New York Rangers, with the first two games at Madison Square Garden.

Thanks to the finesse of the 22-year-old Russian appearing in his first career playoff series — the one who always came to work smiling, the one who had begun studying video of the NHL’s elite centers to aid his transition from the wing, the one who had grown fond of saying, in much-improved English, “This is not my first rodeo” and “It is what it is” — they would see another day.

“Can’t happen to a better guy,” said Carlson, one of several teammates Kuznetsov blew past in celebrating his goal. “I’m so happy for him.”

The first winner-take-all affair of the 2015 Stanley Cup playoffs unfolded with all the predictable drama of the six games that preceded it, none more stomach-churning than when the official signaled Carlson for roughing and the Capitals’ penalty kill, perfect to that point in the series, climbed over the boards. But beyond the stout defensive effort, with Washington allowing its fewest shots on goal in a playoff game since 1990, and the moment Kuznetsov carried the puck through the slot, a line of helpless Islanders left in his wake, Game 7 had already become stuffed with signature moments.

It was Carlson hauling his top-pair partner, Brooks Orpik, off the ice when Orpik’s skate blade broke. It was Washington limiting New York’s dynamic forwards corps to three total shots on goal, fewer than two Capitals had themselves, and the Islanders to 11 overall, their fewest all season. It was Joel Ward leaping like a schoolboy playing hopscotch after his second-period goal, more Game 7 heroism from the right winger, and forward Alex Ovechkin following suit.

It was Coach Barry Trotz standing at the dais, proclaiming he would begin scheming for the Rangers in “probably about 35 minutes,” opening the doors for an entire city to party.

“It’s going to be contagious, I’m telling you,” he said. “All that old stuff, get rid of it. Let’s look to a new era. Let’s build something.”

They had sworn history cast no shadow over them, that their glaring record in Game 7s — five losses over their past seven in this era, none of which saw them score more than two goals — belonged in newspaper articles and bar-counter conversations, and not inside their dressing room. They saw themselves as a new team constructed around the same core, a matured group with 10 players who had appeared in at least four Game 7s, a disciplined bunch who had learned to avoid the emotional pitfalls of these high-pressure moments. The thing about history, they insisted, was that history was meant to be changed. At some point, they hoped, trends would buck. Labels would peel off. Ghosts would disappear.

With four members of the Washington Wizards, winners of their own first-round series here Sunday night, banging on the glass and egging on the crowd, the Capitals stormed through a fast-paced, albeit scoreless, first period. They pestered goaltender Jaroslav Halak, who entered with a preposterous .977 save percentage in four career elimination games against his former team, with 10 shots on goal but never quite cracked him.

The second period featured more of the same, with the Capitals pitching campsites inside the Islanders’ zone, the goal line still padlocked and the building still taut with nervous energy, until with 85 seconds left before intermission the whole place finally exploded. Just outside the crease, Ward shoved defenseman Johnny Boychuk out of the way and, with Halak sitting on his backside, jammed a rebound between the netminder’s legs. For only the second time in seven games, the Capitals had taken a 1-0 lead.

They had 20 minutes to survive until the next round came calling, but it was never that easy — not for this town. Early into the third, Islanders forward Frans Nielsen sensed three Capitals converging onto him and flung the puck toward Braden Holtby, hoping for the best. Holtby dropped into a butterfly, but left open the five-hole. The puck bonked off his left pad and slipped between his legs. The nervous energy returned, until Kuznetsov zapped it away for good.

In early April, on a road trip to Montreal, Kuznetsov tagged along with Orpik to a local tailor and bought new suits. He wore his purchase to Game 5 here in the District, when his three-point outburst rocketed the Capitals onto the cusp of advancing, but not to Game 6, when the Islanders survived at Nassau Coliseum. So as Kuznetsov dressed for the series finale, hoping for good luck, he again chose the blue-and-black attire, which featured a new nickname stitched onto the inside lining, right below the breast pocket.

“Harry Potter,” it read, because teammates told Kuznetsov he always made magic on the ice.