VANCOUVER – In the hockey circles of Halifax, hard by the Canadian coastline of the Atlantic Ocean, the discussion always returns to Liam O’Brien. “Everyone’s talking about it,” said Capitals goaltender Justin Peters, whose brother attends school where the unlikeliest NHL story was raised. “Everyone’s really cheering him on.”

From injured rookie camp invitee to preseason surprise to opening night starter to rotation regular, O’Brien added the next logical chapter to his improbable career arc Sunday, on the opposite end of his native country. At Rogers Arena here in Vancouver, the 20-year-old rookie forward scored his first career NHL goal, just four months after every single NHL team decided that, no, O’Brien wasn’t worth drafting.

“It’s a remarkable story,” Peters said. “It’s a feel-good story. Kind of gives you chills the path he’s taken.”

The 4-2 loss obscured some celebration inside the Capitals locker room, particularly before O’Brien’s stall, but his teammates still retained the same appreciation for an underdog story that has followed O’Brien through this ascent. He skated 8 minutes, 4 seconds against Vancouver, just above his season average. He handed one hit. He attempted five shots, none more important or memorable than when defenseman Mike Green centered a pass and O’Brien jabbed at the puck, like he was poking a friend to wake up.

“Nice play by Greenie to me, a little indirect tip to the net,” O’Brien said. “Found the back of the net. It was nice.”

The Capitals needed that goal, buried beneath an avalanche of second-period tallies from the Canucks, and it again brought them within striking distance. On the bench before their shift, O’Brien, Michael Latta and Evgeny Kuznetsov told each other, “Let’s go get one.”

“It was awesome,” defenseman Karl Alzner said. “It was a great play by him, just working hard, guys throwing the puck at the right spot. It’s always nice when a guy scores his first goal. He deserves it. Played a great game, played hard.”

The celebration took several seconds to commence, because Latta was busy retrieving the keepsake from inside the net, for the mantle in Halifax or, if he prefers, the couch at the hotel in Ballston, where he has lived with the same suitcase since rookie camp began in early September.

A surplus of forwards and a waiver-exempt contract might mean O’Brien soon could head to Hershey, but Coach Barry Trotz has not hidden his admiration for the smiling, tongue-wagging fourth-liner. As the Capitals left Vancouver frustrated over careless puck possession and gap control, O’Brien still stood out. When Washington pulled Peters in the waning moments, Trotz said, he planned to send O’Brien as a reward.

“I thought he’s gotten better and better,” Trotz said. “He’s forcing people out of that role. He’s doing a good job. He’s getting points. He’s physical; he’s on the forecheck; he’s calm with the puck for a young guy. I love where he’s going. For a young man, he’s really taken on a really professional approach to this game to get quicker, get better and learn. He’s working at his game. He’s a good story. You should keep following him.”