Alex Ovechkin flings a shot at Calgary goaltender Karri Ramo in the first period. Ovechkin would later score twice in regulation — and once more in a shootout — as the Capitals win their home opener. (Jonathan Newton/The Washington Post)

A strong start. That was the first item on the to-do list of every Washington Capitals player as they prepared for the beginning of the new season. After last year’s dreadful start, they learned the importance of not falling behind, of setting a positive tone.

As the Calgary Flames, a team expected to reside near the bottom of the NHL standings, threatened to hand them a second loss to start the campaign Thursday night, that first objective appeared in jeopardy.

But after spotting Calgary three goals, the Capitals gradually worked their way back into the contest. Rookie defenseman Connor Carrick kicked off the comeback with his first NHL goal, Alex Ovechkin scored twice and Nicklas Backstrom tied the score late in the third period to force overtime. Then center Mikhail Grabovski recorded a backhand game-winner in the shootout for a 5-4 Capitals victory in the home opener at Verizon Center.

“We were a little sloppy in the beginning there,” Backstrom said. “We weren’t sharp on passes, positioning, stuff like that. It’s always good to have a comeback like this. The points are so important you’ve got to take advantage of it.”

The Flames were physical from the start, finishing solid checks and taking the opportunity for an extra shove or whack after the whistle. Barely five minutes in, David Jones beat Braden Holtby near side with a shot to the upper-right corner. Calgary had a 1-0 lead, and the goal let the air out of what had been an exuberant crowd.

The Post Sports Live crew offers bold predictions for the Capitals season, which opened Tuesday night. (Post Sports Live/The Washington Post)

A little less than three minutes later, the Capitals lost Jack Hillen for the rest of the game after he suffered a leg injury when Flames forward Lance Bouma crunched him along the boards with 8 minutes 10 seconds gone.

Hillen went to play the puck along the boards in the Washington zone when Bouma delivered a clean hit that caught the blue-liner mid-stride. The defenseman’s right leg and knee absorbed the brunt of the impact, and Hillen needed to be helped off the ice. He was taken to a local hospital after the injury and is “going to be out for a bit,” Coach Adam Oates said.

Soon after that, Lee Stempniak outmaneuvered both Mike Green and Karl Alzner in front of the net, settled a bouncing puck and capitalized to make it 2-0.

Washington looked disorganized in its own zone and a step slow throughout the first period. When Alzner went to the box for interference, Jiri Hudler made it 3-0 with a shot to the upper left corner, sending Holtby, who allowed three goals on 11 shots, to the bench. In two starts, the netminder has allowed eight goals on 45 shots. Oates made the switch in part to wake up the rest of the team after its sluggish start.

“I would say we really got outworked in the first period,” Oates said. “I think we were really flat coming out. I really do. Didn’t expect, it but I really thought we were.”

The Capitals’ jump start came from Carrick at 7:30 of the second period. After serving a hooking minor, Carrick emerged from the penalty box unnoticed at first by the Calgary defense. Marcus Johansson sent a head-man pass up ice, springing Carrick on a breakaway. The 19-year-old made a pretty move to pull the puck around the outstretched leg of Calgary goaltender Karri Ramo for his first NHL goal, cutting the margin to 3-1.

“I was pretty upset to have the penalty, so I was trying to have one go the other way,” said Carrick, who received the customary shaving-cream pie in the face from Ovechkin postgame. “Momentum’s a big part of the NHL hockey game. . . . Anything I can do to swing the momentum our way, I’ll be happy to do. And I was lucky to do it tonight.”

Even though Bouma increased Calgary’s lead to 4-1 after a miscue by Michal Neuvirth when he left the crease to play the puck, the Capitals had life. They dished out heavy checks themselves, found their bearings in the defensive zone and started to create some quality offensive chances.

Cue Ovechkin, who needed only 24 seconds on Washington’s first power play of the game to cut the deficit to 4-2 with a blast from the top of the left circle. Just more than four minutes later, the reigning Hart Trophy winner scored again, this time with a shot off a faceoff win by Backstrom. Suddenly the Capitals trailed by just one, were getting a strong outing from Neuvirth (27 saves) and had more than a full period left to play.

But Washington spent nearly all of the first seven minutes of the third on the penalty kill — a stretch that included a lengthy five-on-three for the Flames — and opportunities to even the game were rare until they had another power play of its own.

After an Ovechkin blast was blocked by Curtis Glencross, Grabovski fished the puck out of a mess of bodies in the slot to send a pass over to Backstrom on the right side. He scored on a wrister to knot the contest at 4 with 5:50 remaining in regulation, but the Capitals would still need a pair of tallies — by Grabovski and Ovechkin — to secure a second point via the tiebreak.

“We just stayed calm. We weren’t panicking out there even five-on-three when they have chance to score,” Ovechkin said. “We know if we going to kill it we still had good chance to win the game and go to overtime. The team have character here. You can see it.”