Julius "Dr. J' Erving speaking to the media after he...

Julius "Dr. J' Erving speaking to the media after he had his number retired and raised at the Nassau Coliseum during half time in game between the LI Nets and the Fort Wayne Mad Ants on Sat. Nov. 4, 2017 Credit: Errol Anderson

Before the Long Island Nets could start their future, they had to look at the past.

It was here — back when the NYCB Live’s Nassau Coliseum was just the regular old Nassau Coliseum — where Julius Erving captivated fans. There were days in the 1970s when the place rocked on a regular basis — not because the Islanders scored a goal but because the New York Nets were setting the ABA ablaze, winning two championships in the four-plus years they played here, from 1972 to 1977.

“We took some time last night, with Dr. J being here, to watch a documentary,” coach Ronald Nored said after the Long Island Nets, making their home debut, defeated the Fort Wayne Mad Ants, 115-99. “Our guys didn’t know a lot about him, so we thought it was important to help them understand what this place means, what Dr. J means to the game and the way he shaped the game.”

Even if things have changed a whole lot since then. Just ask Dr. J himself. When he drove up, Erving said, he marveled at how much his old home had changed.

It looked like “something that came from outer space, in the future,” the ABA and NBA legend said. “I was very impressed with the building.” And as for everything around it, “it’s hallowed ground.”

On Saturday, the place wasn’t exactly rollicking. The crowd, an estimated 3,205 for the G-League game, was sparse for the first half and full of kids clamoring to play in the bounce houses behind one of the baskets. It was quiet at times, despite the Nets’ commanding win, and the upper levels were either closed or empty. “I actually expected a [few] more people,” said Kamari Murphy (21 points). “You could tell the kids were into it . . . I heard kids already screaming my name on the side. I don’t know how they know me already.”

But for a moment, as Erving walked toward center court — still a striking presence at age 67 — there was a little glimmer of what used to be. The crowd finally cheered loudly and the scoreboard above the pristine court played the best of Dr. J — of which there was plenty to choose from.

Erving said there still might be glory days ahead for basketball in this new old arena. “They’re giving fans something to be excited about,” he said a few minutes after his banner was lifted up to the rafters, joining two others commemorating the Nets’ two ABA championships. “I think the volume of people who live here — the 20-plus million people that live in Nassau and Suffolk County — there’s no reason why basketball shouldn’t thrive. You don’t have to get all of them to tune in. You just need to show up on the radar.”

And the Long Island Nets did introduce themselves as a team intent on blending into its community. There were family-friendly activities — the bounce houses, a video game truck and balloon animals — and nods to the New York Nets of old (the Rick Barry Free Throw Challenge, in which two kids spent a timeout competing to make the most underhanded free throws, was a nice touch). Fans received replicas of Dr. J’s banner, and a few near the tunnel leading to the home locker room got autographs.

Before the game, Erving’s former mentor, Hempstead Mayor Don Ryan, was presented a lifetime achievement award — one of the primary reasons Erving, who was born only minutes from the Coliseum, made the trip back home.

Nored insisted it was only the beginning. The ABA days are long gone, but much like the new Coliseum, the Nets might be able to bank on some of that nostalgia. “I’m excited about the way we’re building here,” Nored said. “I think the business office has done a good job of selling tickets and getting people excited. It’s hard to sell a product that people have never seen before, but they really worked hard and I thought the guys really embraced the crowd. Last year, we played in an empty Barclays Center, which was great, but it was good to finally play with some fans.”

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