Where Alex Ovechkin is concerned, there is a clear demarcation line: June 7, 2018. That’s the night his Washington Capitals beat the Vegas Golden Knights one last time. That’s the night he hoisted the Stanley Cup. That’s the night his legacy changed.

But to understand where Ovechkin sits as he enters his 16th(!) NHL season Thursday night in Buffalo, it helps to revisit where he stood as he entered that 2017-18 campaign. He was, it appeared, an icon in decline. He was, without question, doubted.

“He’s going to have to think of ways he can evolve into a player that still has a major impact on the game,” his general manager, Brian MacLellan, said in May 2017.

“I don’t want to stay on the same level,” Ovechkin himself said back then. “I want to be better.”

Three full seasons later, Ovechkin has not just been better. He has been dominant. He has the Cup, and that counts. But given the mandate of 3½ years ago and the milestones still ahead, Ovechkin’s legacy won’t just be that he’s a champion and the greatest goal scorer of his generation. It will be that when his skill and his will appeared to be waning, he transformed himself.

“He’s answered every challenge,” MacLellan said this week. “He finds ways to adapt. He finds ways to score goals.”

And even at 35, he’s scoring more of them than anyone in the league. He is better by bunches.

“Ovi’s always going to be Ovi, I think,” longtime running mate Nicklas Backstrom said. “It doesn’t matter what age he’s at. Everything he brings on a daily basis: He can play physical. He can score goals. We all know that. There’s no limits with him. I think it says it all about his character.”

Since the beginning of the season in which the Caps won the Cup, no one has scored more goals or scored at a higher rate than Ovechkin. In those three seasons, he led the NHL in goals all three times — 148 over 231 games played. That works out to 0.64 goals per game. The league is supposed to be getting younger and faster. Yet 23-year-old Auston Matthews (0.59) of Toronto, 24-year-old Connor McDavid (0.54) and 25-year-old Leon Draisaitl (0.51), both of Edmonton — none can match the gray-tipped Ovechkin. No one in the game can.

What’s more impressive is how those goals have come. Ovechkin has always been a machine on the power play; indeed, he needs just six power-play goals to pass Brett Hull for second all-time, just 15 to blow by Dave Andreychuk for most in history. You get the feeling that in a decade, he could bring a walker out to the left faceoff circle and still fire off one-timers that beat the best goalies in the world.

But part of the Capitals’ challenge to Ovechkin following that 2016-17 season — the season that ended with a knee-buckling Game 7 loss to Pittsburgh — was to get better five-on-five. That year, he scored 17 times on the power play and 16 at even strength — the only season in which he has had more goals with the man advantage, a worrying sign. Since, he has 100 goals at even strength — more than anyone in the league by a whopping margin. (Matthews and McDavid are tied at 89 apiece.)

“His five-on-five play, at that point, maybe the production wasn’t as much,” MacLellan said. “ . . . He’ll always have the power play and the one-timer. I think he’s learned different ways to score goals or different ways he can contribute. At some times, at points in his career, he’s probably looked a little slower but picked up his conditioning. He’s adjusted the whole way. I would bet on him continuing to adjust, finding ways.”

His record shows it, regardless of the style the league trends toward. In his first seven seasons, Ovechkin led the NHL in goal-scoring twice — his Hart Trophy-winning MVP seasons of 2007-08 and 2008-09, back-to-back campaigns when he combined for a staggering 121 goals when he was 22 and 23. But in his past eight seasons, more than half his career, he has led the league in goal scoring seven times, maintaining his goals-per-game rate even as the league averaged slightly fewer goals each night. His body gets older. The pucks keep going in.

And so continues the climb up the NHL’s all-time scoring list. Right now, with 706 goals, he’s eighth — two behind Mike Gartner, 11 behind Phil Esposito, 188 behind Wayne Gretzky, the all-time leader. Even at 35, anything’s possible.

“It’s obviously impressive what he’s doing and what he’s done,” MacLellan said. “Everybody wants to see him continue to do it to see how far he can go.”

Still, it’s hard to look at that positioning now, with Ovechkin closer to 40 than 30, without fretting over all the time he lost to reasons beyond his control. What might have been his rookie season of 2004-05 was gobbled up by a lockout, as were 34 games of 2012-13 — his most recent Hart Trophy-winning season as the league’s MVP. The coronavirus pandemic shortened the 2019-20 regular season by 13 games, and the season that begins Thursday is docked another 26. Even if you just take the games lost since 2012-13, that’s another 40 to 45 goals Ovechkin might have scored — which would put him fourth already, behind just Gretzky, Gordie Howe and Jaromir Jagr.

Oh, well. Forget the might-have-beens for a minute. There’s still plenty of what might be. What’s remarkable about those on the all-time goal-scorers list is Ovechkin’s scoring rate among them. No one among the top 10 goal scorers has topped Ovechkin’s career mark of .613 goals per game. Now, it’s logical that number will fall as Ovechkin ages. Still, even if he’s at a goal every other game — a significant drop-off from his career average — he could reach Gretzky late in the 2024-25 season, when he’s 39. Gretzky scored his last goal when he was 39.

So now, another season, and the climb continues.

“I would put 35,” Backstrom said, projecting Ovechkin’s total in the upcoming 56-game campaign. “But I’m putting it low, so hopefully it’s over that.”

The last time the league put Ovechkin low came before he had won a Cup, before he had changed his body and his game. Thursday will be his 1,153rd regular season game. It might bring his 707th regular season goal — or more. What I have learned, after all these years, is not to put limits on him. When I have, he has blown right past them.

“I would not bet against him,” MacLellan said. “He can continue to be successful as long as he wants, as long as he’s engaged mentally. He’s a strong-willed person. He brings that to the rink, and whatever challenge that comes, he applies that to it.”