On that night all those years ago, their roles were sketched out clearly. Alex Ovechkin was a hero in Washington, where he salvaged a sport, but simultaneously could be cast as an evil, masked villain in Pittsburgh. Sidney Crosby was a symbol of the no-nonsense, hard-working people in the Steel City, but nothing more than a whiny crybaby in the nation’s capital.

This was May 2009, Game 2 of the Eastern Conference semifinals right here at Verizon Center. When Ovechkin poured in his third goal of the game, giving his Capitals a 4-2 lead over Crosby’s Penguins, the hats rained down from the stands. Workers scooped up the first wave, filling trash cans. And when still more floated to the ice, Crosby skated over to the referee.

“I was just asking if he could make an announcement to ask them to stop,” Crosby said that night.

Introducing Crosby, in the eyes of Caps fans, the best player on Earth always complaining about something. Ah, memories.

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That night, both Crosby and Ovechkin ended up with hat tricks. That month, the Penguins came back in the series to beat the Capitals, taking the seventh game on Washington’s home ice. That June, Crosby lifted the first of his two Stanley Cups, the first of two treks through the playoffs that have gone through Ovechkin and the Caps.

There we were then, and here we are again. It is both unfair and inevitable that these two players — a soft-spoken Nova Scotian and a hard-driving Muscovite — will be forever linked. Back in that initial playoff meeting, it seemed as if this would be an annual spring rite: Ovechkin vs. Crosby, Capitals vs. Penguins. That hasn’t happened. The second-round playoff series between the pair that begins Thursday at Verizon Center is just their second postseason meeting since that series that outlined their roles so long ago.

But even as other themes will emerge over the course of the next two weeks, history almost certainly will define this series as Sid vs. Ovi — again. With apologies to . . . ah, forget it. With apologies to no one: They are the two transcendent hockey players of their era. Whenever they meet, the default position is simple: It’s about them.

“They’re always going to be compared because they came in the same era, and in a lot of ways they sort of saved our game, Sid and Ovi together,” Capitals Coach Barry Trotz said before the season, which serves only to emphasize how these two characters hang over the entire league. “. . . They came out of the [2004-05] lockout, two young guys [who] brought a lot of attention to the game. They brought a lot of flair to the game, face and name recognition, and put an excitement back into the game. So they’re always going to be compared.”

[For Alex Ovechkin’s agent, the Capitals have been a lifelong passion]

They were compared back then. They were compared last spring, when the Penguins ousted the Capitals in six games in this very same round. They will be compared this month. And they will be compared decades from now, when their careers are over and they’re enshrined — perhaps next to each other — in the Hockey Hall of Fame in Toronto.

“We respect each other,” Ovechkin said this week, and now, as he is in his 30s, you believe him. That might not have been the case that night eight years ago. There were times, over the course of this relationship, when they seemed to have not-so thinly veiled disdain for each other. That fit the story line, too. Other than hockey, what did they really have in common? What are the similarities?

“Not many,” said Caps defenseman Brooks Orpik, a former Penguin and therefore one of a small handful of people who have played with both.

Crosby is a centerman. Ovechkin plays the wing. Crosby passes first, with 645 assists to his 382 goals. Ovechkin is and always will be a sniper first, as his 558 goals (alongside 477 assists) attest — trailing only ageless Jaromir Jagr and Jarome Iginla among active players. Crosby missed significant time over the course of several seasons battling injuries, most notably concussions. Ovechkin has been darn near indestructible, never playing fewer than 72 games in a season not interrupted by labor strife, 10 times playing at least 78 games. Crosby scored the overtime game-winner to lift Canada to gold in an Olympics on home soil. Ovechkin was part of a Russian implosion at his own home Olympics. Ovechkin has a 3-2 edge in Hart Trophies as the NHL’s MVP. Crosby has, of course, the more important edge: 2-0 in Cups.

Look at those numbers. We have a treasure trove of information to evaluate each player, exactly what we didn’t have back on that night of the dueling hat tricks.

We know, too, that they’re different players and people at 31 and 29 than they were at 23 and 21. “We’re not buddies,” Ovechkin said. “We’re not friends.” And yet, as evidenced by hanging out at the All-Star Game or sharing jokes at awards ceremonies over the years, they don’t quite despise each other anymore, either.

“They come from different worlds,” Trotz said. “. . . What you find is: They recognize their importance to the game and their franchises. I see that in how they carry themselves for those franchises — and for their countries. They’re very proud of both.”

As the series begins, know that your eye will be drawn to No. 87 in black and No. 8 in red, just like it was in 2009. But know, too, that they’re not kids preparing to carry the league. They’re veterans who have carried it for a decade.

“That battle between me and him, it’s great,” Ovechkin said. “I think me and him enjoy it, you guys enjoy it, fans enjoy it. But right now, it’s not about me and him. It’s about Caps and Penguins.”

What’s the difference?