Even in the beginning, there were believers.

What Mike D’Antoni was trying to do in the mid-2000s was revolutionary, installing a fast-paced, small-ball system into what was then a more-plodding NBA. But there were early adopters, those who saw the vision in Phoenix, who were confident it could succeed at basketball’s highest level.

Alvin Gentry wasn’t one of them.

“I wasn’t in that camp at all,” said Gentry, then an assistant to D’Antoni. “I was just such a traditional guy that I was like, ‘Oh, man, I don’t know if we can play this way.’”

Fast forward — emphasis on the ‘fast’ — 11 years, and Gentry is a full-on convert. A version of the “7 Seconds or Less” system D’Antoni brought to the NBA won an NBA title last season for head coach Steve Kerr and Golden State.

Gentry was the associate head coach there. Now he’s spreading the go-go-go gospel in New Orleans, instituting a system that will pump up the pace on a team that finished last season under coach Monty Williams 27th out of 30 NBA teams in pace of play.

It’s considered an ideal fit for the Pelicans and particularly star Anthony Davis, who says basketball experts have told him “I’ll probably score 50 a couple times” this season under Gentry’s tutelage.

Pace is the NBA’s movement of the moment — in New Orleans and elsewhere.

Like the teams which employ it, it’s gone a long way in a short time.

Gentry wasn’t alone in 2003, when he wondered what the Suns were getting into. D’Antoni remembers a culture of support inside the Phoenix organization and of skepticism virtually everywhere else.

“They didn’t think it could last in a season, and then it definitely wouldn’t last in the playoffs, and you couldn’t win that way,” D’Antoni said. “All the way through, I think people had very serious doubts about it.”

And then the movement started.

Birth of a System

Today, he’s regarded as a revolutionary, but D’Antoni wasn’t always such a rebel.

Though he’d played up-tempo as a collegian at Marshall and preferred it as a pro at stops in the NBA, ABA and overseas, his coaching career began at Olimpia Milano in Italy employing more run-of-the-mill than run-and-gun.

“I started off coaching in the same way, just like everybody else,” D’Antoni said. “Just lining up the traditional way.”

But D’Antoni saw the future coming.

European big men in the ’90s, D’Antoni said, lacked the athleticism and strength of NBA frontcourt players, but they could pass and shoot 3-pointers and put the ball on the floor “a lot easier” than their American counterparts, D’Antoni said.

In about his third season at Olimpia, D’Antonio — blessed with a team gifted enough to play smaller lineups without getting battered on the backboards — began to push the pace. His offensive philosophy — push the ball upcourt and take the first available good shot, as early in the shot clock as possible — was born then and grew from there.

“I thought even back then it was more important to have the floor spread” than to have size, D’Antoni said. “We could get guys shooting layups instead of shooting post-ups. We could get guys shooting 3s instead of shooting contested twos. We were able to get guys to the free-throw line by spreading the floor and having quickness.”

Those tenants remained at the core of what D’Antoni ran in Phoenix, where he moved 6-foot-7 Shawn Marion to power forward and played Amar’e Stouemire at center. In D’Antoni’s second season with the Suns — Gentry’s first with him as an assistant — Phoenix averaged 110.4 points per game and finished 62-20.

You can see that basic blueprint in what Golden State did last season and what Gentry will try to do this season with the Pelicans.

Layups over post-ups. Threes over twos. Pace over everything.

It’s a style, Gentry said, that players like to play and fans love to watch. It emphasizes basketball skill and IQ over set plays and post-up traditionalism. When it is at its best, Pelicans point guard Jrue Holiday said, it’s “kind of like a work of art.”

And it is really hard to play.

The Needs for Speed

There are exceptions, but for the most part, Davis said, “Everybody says they want to play fast.”

It’s easy to see why. A faster pace means more possessions. That means more shots, more offensive opportunities to spread among players. A team that shoots quickly wastes less time running through tedious offensive sets. It plays more naturally, the way players learned to play as they grew up.

But having all that fun takes a lot of work.

“Everyone assumes it’s all about the perimeter players — the guards and the small forwards — being able to run,” TNT analyst Reggie Miller said. “No. Your bigs have to get out and run in transition as well. So you’ve got to have that commitment.”

To that end, Davis said, the Pels have committed to cardio. Players large and small run after practice on treadmills and in laps around the court, he said, the better to prepare themselves for the pace to come.

But “pace” isn’t the same as speed, and it’s an important distinction. Though the D’Antoni offense is designed to seek the first, best shot — preferably in seven seconds or less — it’s about more than running at breakneck speeds.

“It’s more of a consistent pace,” Holiday said. “You don’t have to run fast all the time. It’s more being consistent in the flow, so every time we get the ball it’s a certain type of tempo, it’s a certain type of flow.”

In its own way, an offense that Davis describes as “free-flowing” takes as much discipline as any in the league. It requires running on every possession, to get shots before a team sets its halfcourt defense. It needs a point guard who pushes the ball, wing players who run to spots and big men who set picks with precision.

Practicing it, D’Antoni said, requires coaches “to let go a little bit of the control that you have in practice a lot of time.” Players have to make mistakes on the run and learn from them. And it takes time. Though the Pelicans averaged about 10 possessions more this preseason than they did last season, the offense is very much a work in progress and likely will remain so for some time.

“I think it’s something that’s easy to say but very difficult to do,” Gentry said. “What you have to do is, it has to become a mindset of your team.”

And it helps if you have players who fit the system. Gentry has several, including two D’Antoni said are tailor-made for it.

When he’s healthy, D’Antoni said, Holiday is one of the league’s most underrated point guards, a player with the motor, court vision and commitment to detail to run the system Steve Nash made famous and Steph Curry guided to an NBA title.

And the 6-foot-10 Davis is in some ways the prototype big man for a system that spreads a defense. He’s dominant rolling to the basket in the pick-and-roll, can dribble past a smaller defender and now has a 3-point shot in his arsenal.

“I’m biased, but I think this system will fit his talents immensely,” D’Antoni said. “He’s really good. But I think what Alvin’s going to do will maximize all the talents that he has, which is incredible defensively and offensively. I think it’s suited for him. I think Alvin will get everything he can out of him, and that’s a lot.”

Still, learning to play quickly can be a slow process. And the Pelicans may not have much time.

Learning Curve

Holiday’s job is to make the Pelicans offense go. For now, he’ll be doing it 15 minutes at a time as he plays under a minutes restriction during his recovery from a right-leg stress reaction.

Tyreke Evans was made to play at this pace, Gentry said. He won’t get a chance to prove it for six to eight weeks as he works his way back from right knee surgery. Backup point guard Norris Cole is out indefinitely with a high ankle sprain.

With so little experience at point guard — and so many odd lineup combinations necessitated by injury — the Pelicans, who won 45 games last season before losing to the Warriors in the first round of the playoffs, may need time to get in a groove. ?“Let’s face it, any time you try to speed up, you have the possibility and potential to make more mistakes,” TNT and NBA TV analyst Brent Barry said. “And the more mistakes you make, especially against the teams in the Western Conference, you’re not going to win a lot of games having a ton of turnovers.”

So far, the Pelicans have limited turnovers even while increasing possessions this preseason. But regular-season defense looms, and injuries remain an issue.

New Orleans might not start fast, but by the season’s home stretch, Gentry — once a skeptic, now a convert — is confident the Pelicans will be up to speed.

“It takes a little while,” Gentry said. “I think we would obviously be much further along right now with all healthy bodies, but we didn’t have that option. So we’ll just have to keep plugging away, and I think we’ll get there.”