Alex Ovechkin celebrates the second of his four goals in the Capitals’ rout of Montreal on Saturday night. (Nick Wass/Associated Press)

As the replay of the Washington Capitals’ fourth goal flashed across the video board, the applause in Capital One Arena grew louder Saturday night. One hat dropped onto the ice, then another, then another as fans squinted to see who last touched the puck.

There was no doubt about Alex Ovechkin’s first two goals, stunning shots from his favorite spot at the left faceoff circle. The third required a few extra looks; Evgeny Kuznetsov’s shot was tipped before going into the net, but was it Ovechkin’s stick that got a piece of the puck? Replay confirmed it was indeed Ovechkin’s goal, giving him hat tricks in back-to-back games to open the season.

Ovechkin added a fourth goal in the second period, and the Capitals cruised to a 6-1 win against the Montreal Canadiens in their home opener. It was a historic night for Washington. Ovechkin became just the fourth player to open the season with back-to-back hat tricks, and he’s the first to accomplish the feat in 100 years; three players did it in the first NHL season.

Is this a perfect start to the season?

“Well, obviously, yeah,” Ovechkin said. “It’s a fun time when you play like that and your line feeling it. It’s fun to play.”

More history came on the Capitals’ sixth goal when Devante Smith-Pelly’s shot bounced off forward Nathan Walker and into the net. Walker became the first Australian to play in an NHL game when he took his first shift Saturday night. With his family in the stands, Walker also notched his first goal.

It was initially credited to Smith-Pelly, who immediately recognized the shot deflected off Walker.

He asked for the puck as a keepsake for Walker and, when the scoring change was announced, Walker’s mother, Ceri, stood and wildly waved an Australian flag, cheering with the rest of the fans. Ovechkin skated over the bench to give Walker a few taps on the helmet.

“It was amazing,” Walker said. “As a kid, you’re always thinking you’re going to play in the NHL one day and be there. I just tried to take it all in and enjoy myself.”

Goaltender Braden Holtby quietly recorded 38 saves in a home opener few will forget. The last time the Capitals played a game that counted here, it was a 2-0 loss to the Pittsburgh Penguins in Game 7 of the teams’ second-round playoff series. The disappointment from the postseason exit hung over the team and fan base throughout the summer, but Saturday night’s rout, with milestones and personal achievements and ovations, was another step in moving forward.

Twenty seconds into the game, Ovechkin ripped a turnaround slapper that resembled a baseball swing, sailing the puck through two Montreal players and over Canadiens goaltender Carey Price. On the next shift, T.J. Oshie punched in a rebound to lift the Capitals to a 2-0 lead. Two shifts later, Washington’s fourth line drew a penalty, putting the Capitals on the power play. Ovechkin wristed the puck over Price once again for three goals in less than three minutes.

But it was Ovechkin’s third goal, the subtle one that required an extra look, that will make Washington’s coaches and management happiest. With the Capitals’ lineup deep and balanced last season, the team didn’t need to rely on him as much, and his minutes were cut by roughly two per game. His goal production fell to 33, down from 50 the year before, and just 16 of them were at even strength, a career-low.

With several players due raises this summer, Washington experienced its most significant roster turnover in years, parting with top-six forwards Justin Williams and Marcus Johansson because of salary-cap constraints. Those two alone scored 48 goals last season and, as the Capitals incorporate several new faces in the lineup, more burden falls on Ovechkin to produce.

Along with asking Ovechkin to make some changes to his training so he could better adapt to a speedier NHL, the Capitals also wanted to see him score more “dirty” goals in front of the net, where scoring takes the most work. And there he was on Saturday night, getting the blade of his stick on Kuznetsov’s shot.

“You want to be at front of the net,” Ovechkin said. “I think [former Capitals forward] Brooks Laich said, ‘If you want money, go to the bank. If you want goals, you go to the front of the net.’ Or whatever.”

By the end of the first period, fans had calculated he was on pace for a 246-goal season. The Canadiens’ 18 skaters had managed seven shots on goal through 20 minutes. Ovechkin had six shots alone, and he had six goals in his previous two full periods (plus a five-minute overtime period) after scoring three in the third period in Ottawa on Thursday. His 19th hat trick tied Peter Bondra for the most in franchise history. He added a fourth goal when a puck pinballed off several Canadiens players and into the net.

As the videoboard showed a replay of his hat trick in the third period, Ovechkin smiled on the bench. He and the Capitals both proved something Saturday night.

“Sometimes you just have to move forward, obviously,” Ovechkin said. “It was kind of a position where everyone thought we were going to be unstoppable. We did it in the regular year, but in the playoffs, something happened and we lost. We lost couple of key guys, obviously, but right now, you can see Walks play well. We signed good players, and they stepped up.”

The captain did, too.