The Washington Capitals entered the third period Wednesday night facing their stiffest test of how far they’ve come as a group. Trailing the New York Rangers by three in Game 4 in a rabid Madison Square Garden, they roared back with one of their most dominant showings.

The Capitals scored three goals, two by rookie center Marcus Johansson, on 13 shots in the third to knot the score and force overtime. With momentum on their side in the second overtime period, Jason Chimera scored the game-winner as he knocked a loose puck into the Rangers’ net unassisted to clinch a 4-3 triumph in the 93rd minute of play.

It was a gritty victory that put the Capitals up three games to one in this Eastern Conference quarterfinal after many might have written them off when they trailed by three. It also marked a win in a game that featured as many emotional ebbs and flows as an entire series might, a contest that could offer a big momentum boost for the victor.

The play that led to the game-winner, though, was a broken one. Chimera took a shot that was partially blocked and fluttered in on New York goaltender Henrik Lundqvist (49 saves), but as he tried to cover the puck, Marian Gaborik poked it away in an effort to keep it out of harm’s way. The puck hit Chimera and dropped to the ice.

“It felt like forever when it hit my chest and [then] went down to my stick,” Chimera said. “It was nice; it was a good effort by us in the third period to find a way to come back.”

Jason Chimera puts the game-winner into Henrik Lundqvist’s net at 12:36 of the second overtime. (John McDonnell/THE WASHINGTON POST)

To even send the game into the sudden-death periods, Washington needed to mount one of its more memorable comebacks of the season after spotting the Rangers a 3-0 lead through two periods. Two minutes 47 seconds into the third, the Capitals began to claw their way back.

Alexander Semin took a shot that sent the puck knuckling through Lundqvist, who couldn’t find the loose puck behind him. Semin followed up on the play, which was not whistled dead by the referee behind the net, and poked the puck over the goal line to make it 3-1.

Fifty-seven seconds later, the Rangers lost Johansson directly out in front, where he knocked the puck home. At that point, Washington had created something of an informal power play. The action on the ice was still five-on-five, but the Capitals had finally established sustained pressure in the offensive zone and were finding success near Lundqvist’s crease.

Washington had entered the period looking for momentum to build off, but having cut the deficit to one the players started to have faith in the possibility of capturing a win yet.

“You get one and you never know. When we got both goals really quickly, I thought we believed we were in it,” Coach Bruce Boudreau said. “I never knew. All I did was hope, but I tried to contain my excitement. I just wanted to be on an even keel, and the players, they felt that there was a potential comeback in the making.”

Capitals goalie Michal Neuvirth (36 saves) made a few nice stops, including a shot off a rebound by Brian Boyle, to ensure the Rangers couldn’t jump ahead further until, finally, Washington caught up.

Just past the 12-minute mark, Washington defenseman John Carlson fired a shot from the point with heavy traffic in front of the New York net that was redirected by Johansson to complete the rally and tie it at 3. It was a mighty shift from the way the first 40 minutes went.

“It felt good for us,” said Johansson, who scored the first two NHL playoff goals of his career. “No one expected us to come out with a tie after that second period, but we believed in ourselves and we went out and did what we were supposed to do, and that’s how you win games. I think they got a little shaky after that.”

During a radio appearance earlier this week, Boudreau said Madison Square Garden, the NHL’s oldest building, was “nothing” and “not that loud.” Whether it was intended to create a stir was irrelevant, because the comments provoked the New York faithful to make themselves known, and the sold-out Garden was raucous when the teams hit the ice.

Rangers fans quickly turned to their new enemy, chanting “Boud-reau sucks!” in unison. They even replaced Denis Potvin’s name with the coach’s in the famous “Hot Cross Buns” tune that Rangers fans have been singing since 1979.

With the boiling atmosphere as the backdrop, the Capitals and Rangers started the fourth installment of the series as they have each game prior, with plenty of hits on both sides. Both teams garnered scoring chances in the opening period, but as it was in the three previous games, the first 20 minutes ended in a scoreless tie. Neither the Capitals nor the Rangers have scored a goal in the opening frame this series.

The Rangers would tally the first goal, though, something that isn’t to be underestimated with legions of supporters boosting the air in the arena to their favor. Less than six minutes into the second, Artem Anisimov chipped the puck from behind the Capitals’ goal line. The shot redirected off Matt Hendricks’s skate and past Neuvirth to give the Rangers a 1-0 lead. It was the second bounce in as many playoff games that has gone against the Capitals and it only galvanized the Rangers.

The contest didn’t unfold in the same tedious, defensively methodical manner that both teams had exhibited previously. Rather, each made their share of turnovers and committed bad line changes, leading to more odd-man rushes and breaks on both sides.

The Rangers were creating the better opportunities as the second period progressed into a crescendo before the 14-minute mark. Ruslan Fedotenko made a no-look pass to the right post of the Capitals’ net, where an unguarded Marian Gaborik swept the puck into the net to make it 2-0.

Seven seconds later, Brandon Dubinsky corralled the puck as it bounced off the boards to make it 3-0.

It was then that a rabid crowd at Madison Square Garden started yelling a question, presumably to Boudreau. “Can you hear us?” They screamed, growing louder by the second, but these weren’t the same Capitals who suffered a blowout loss here back on Dec. 12.