MIAMI — Jimmy Butler returned and reinforced his greatness. The Knicks and Julius Randle? They just folded.

Saving a terrible time to produce one of its more anemic offensive performances, New York was crushed by the Heat, 105-86, leaving Saturday with a 2-1 series deficit.

Butler was a difference maker with a game-high 28 points and a jolt of intensity after he sat Game 2. But he wasn’t the Knicks’ biggest problem Saturday.

They mostly have themselves to blame for the belly flop in Biscayne Bay.

“We paid the price,” coach Tom Thibodeau said.

The Knicks, trailing wire-to-wire, shot just 34 percent overall while missing (shield your eyes, children) 32 of their 40 3-point attempts. The misfiring was widespread.

Julius Randle, moving at ¾ speed through his abysmal 38 minutes, scored just 10 points on 4 of 15 shooting. His game ended with a lollygag back on defense with about a minute remaining, allowing Cody Zeller an open dunk in transition.

“I’ve got to find a way to play better,” he said.

Jalen Brunson, clearly laboring with injuries to both feet, missed all five of his 3-pointers. The Knicks bench, an issue since the start of the series, was again ineffective, with Immanuel Quickley, Obi Toppin and Quentin Grimes combining to miss 12 of their 16 3-pointers. Quickley also sprained his ankle in the fourth quarter when Bam Adebayo dove into the guard’s leg.

So there were no positives for the Knicks on Saturday. It was a wipeout from the paint to the perimeter.

Butler’s impact, meanwhile, was immediate. He scored on Miami’s first possession, selling a pump fake before converting a  floater. He stacked the box score in the first quarter – 10 points, two blocks, two rebounds, one assist, 5-for-9 shooting.

“They came in tough, they started out physical,” said RJ Barrett, who missed 11 of his 16 shot as the Knicks were outscored by 32 points in his 25 minutes. “Jimmy had like eight points in the first two minutes or something. They just came out strong. They threw a punch and we battled throughout the game, but they started out great and they had a good game.”

Somehow the Knicks never recovered from Butler’s initial onslaught. They trailed by double digits for the final 35 ½ minutes.

“[Butler’s] been the best player in the world lately, so can’t be mad at having him on the floor,” said Heat guard Max Strus, who finished with 19 points. “Having him always helps. We just try feed off of everything he gives us. And everyone’s just trying to help him. He’s been so great. We just want to do our job and be great for him.”

Butler also turned his right ankle — the same one that kept him out of Game 2 — while falling to the court on a drive in the third quarter. He continued to play and moved well in the fourth quarter, helping seal the blowout.

“I’m comfortable,” Butler said, “and confident.”

Butler had six days to heal the original injury by skipping Game 2, and Knicks coach Tom Thibodeau was well aware of the challenge. Butler showed up and ignited the Miami crowd, which is famously fickle and arrived fashionably late Saturday.

The Knicks had no response.

“We got it down to 10 a couple times, but then we never could get that next one,” Thibodeau said. “That’s the tough thing. And they played from a lead the whole game. You give a team a cushion, it’s hard. Every time we seem to have a crack at getting back into it, we didn’t make the next one.”