Welcome back Ben Simmons.

His return showed just how much the Nets missed him.

With their only All-Star finally back on the floor, the Nets looked like an entirely different team — a better one.

He gave them pace, and a transition game — and a 147-114 rout of Utah before a crowd of 16,054 at Barclays Center on Monday night.

After missing 38 straight games with a nerve impingement in his back, Simmons played for the first time since Nov. 6.

But there was no rust, just playmaking and energy that the Nets had so sorely been lacking.

And it didn’t take him long to find his rhythm — just a couple of seconds.

“When did I feel like I was back in business? When they let me play. When I was cleared to play,” said Simmons, who flirted with a triple-double. “I told them as soon as we checked in. They know what time it is.

“Certain guys know what it’s like to play with me and where their shot’s going to come from. So for us, it’s easy. It’s just about sharing the ball and playing the right way.”

Mikal Bridges’ game-high 33 points led eight Nets in double figures.

But Simmons was the man of the hour, with infectious ball movement.

He had 10 points, a game-high 11 assists and eight rebounds, a stellar plus-27 in just 18:14.

“Shout-out to Ben,” Lonnie Walker IV said. “The beginning of the game, he was just locked in. He really brought that energy for us, really changed the game as far as just pushing the rock in transition.”

Simmons’ passing was contagious, as the Nets had a season-best 41 assists with just eight turnovers. It was the first time in team history they had notched 40 assists and fewer than 10 turnovers.

“Once he said he was ready to go, I had no qualms that he was going to be able to push the pace for us and get back to the high-energy, high-octane pace that he’s played with this group,” Jacque Vaughn said. “You see how he just impacts other people. He makes other dudes better, and he likes doing that.

“When you get a guy that wants to do that on a nightly basis, it’s infectious. And so, just the ball movement tonight. He was the reason for that. The way it was sprayed around — 40-some assists — you can’t ask for anything more, especially with the time that he’s missed.”

Simmons was only the second player in history with 10 points, 10 assists, five rebounds and no turnovers to go perfect from the floor.

The other? Nikola Jokic.

Simmons powered a usually deliberate Nets team to 28 fast-break points.

“Yeah, it’s always a fast break when I have the ball,” Simmons said. “Yeah, just pushing, pushing the pace. … Not many teams are ready for a team that’s pushing the ball every single time down the floor, you know? So it gets guys crossmatched, different matchups that you want for us offensively. And then just reading the defense and seeing what they’re gonna give us.”

Coming off the bench in the first quarter and immediately sparking a 20-7 run in his 4:34 was his most important contribution.

But his steal off Lauri Markkanen — tapping the ball up over the Jazz All-Star and to himself for a breakaway dunk and 92-77 lead with 3:25 left in the third — was by far his most impressive.

The Nets poured it on, with back-to-back Simmons layups padding the cushion to 26 and 126-100 and 128-102 with 5:36 left.

He departed with 3:27 and the Nets up by 29.

The high-priced and oft-injured Simmons entered Monday having been limited to just six games this season, and 48 total since Brooklyn acquired him at the 2021-22 trade deadline.

With Simmons earning $37.9 million this season and $40.3 million next season, getting victories wasn’t the only thing the Nets are desperate for.

They desperately need to get Simmons right, and keep him that way.