MIAMI — Jimmy Butler keeps insisting the superhero called “Playoff Jimmy” doesn’t exist.

He’s lying.

He got the first rebound Saturday against the New York Knicks, went the length of the court and hit Game 3’s first shot. That answered if the sprained ankle that kept him out of Game 2 was fine.

He had eight of the Miami Heat’s first 15 points despite the Knicks running two defenders at him to set the tone for the day. He blocked two shots in the first half and finished with 28 points in a coast-to-coast 105-86 win.

“He was pretty good today,’’ Knicks star Julius Randle said, economical and understated with his words.

How do you spot the all-time greats lurking amid the sometime greats? They’re the players that keeping answering the moment, the ones who everyone follows, who don’t suffer from the vagaries of inconsistency from game to game.

Butler is again doing, night after night in these playoffs, more than LeBron James, Dwyane Wade, Alonzo Mourning or any Heat legend was asked to do in any playoffs. He’s averaging 36.3 points, seven rebounds and five assists these playoffs while shooting 59.4 percent.

Butler’s 28 points Saturday came with an asterisk. He sat there through most of the fourth quarter of a blowout game, sometimes leaning back on the bench, legs crossed like an art critic more than a star whose good work looked done.

But when New York scored eight straight points to cut the Heat lead to 95-81, Erik Spoelstra gave the call and Butler came in to spin the day on his finger one more time.

He took a pass on the baseline, sank a 14-footer as the shot clock expired. That was the Mona Lisa smile on the day. The Heat are Butler’s sprained ankle away from sitting on a blowout series.

“It’s the overall confidence level your team has that you can always get the ball to him and know you’ll get something efficient and coherent,’’ Spoelstra said “At the same time, we had other guys stepping up.

Sure, there are others playing good roles. Bam Adebayo had a strong defensive day to go with 17 points and 12 rebounds. Max Strus had 19 points. Spoelstra is a maestro in a manner any basketball aficionado should appreciate in shutting down the Knicks offense.

“Did we win the glass today?” Adebayo said, looking at the rebound total on the stat sheet. “Yeah, we did by two.”

This again is Butler’s team, and again his time. The Heat weren’t supposed to be this close to anything special after this season. They were close last year when Butler led them in scoring eight of their final 11 games against Philadelphia and Boston when a trip to the NBA Finals fell short on his missed 3-pointer.

They were close three years ago when Butler led them in scoring in the first five games of the NBA Finals against the Los Angeles Lakers before his body dropped from exhaustion in the sixth game.

This borders on sacrilege in Heat circles, but Butler is doing what Wade didn’t. Remember in the 2009 playoffs when the Heat were run off the court by Boston and Wade, feeling all alone, said, “This won’t happen again.”

That ushered in The Big Three Era. Butler is The Big One Era. He’s asked to be LeBron or Wade or Chris Bosh every game. He’s scored at least 25 points in each game these playoffs.

“I was definitely out of rhythm,” he said of Saturday after missing the previous game. “I shot a lot of shots that …”

He made a sour face.

“I want to take a look at the film, but that’s what great players do,’’ Knicks coach Tom Thibodeau said of Butler. “You’re going to put more than one (defender) on them. Whether it’s a pick-and-roll or post-up, you load up pretty good to him.”

There were times during this regular season, lots of times, when the Knicks were making headlines the Heat weren’t. They brought a winner to Madison Square Garden again. Jalen Brunson was the star they’d waited on. They were the feel-good story the Heat weren’t.

Only here it is, second round of the playoffs, and the Heat are making the headlines. They look nothing like their regular season in good part because Butler looks nothing like Regular-Season Jimmy.

Spoelstra said after Game 3 he and Butler were, “fighting both our instincts,” in limiting his star’s minutes some regular-season nights. Those times are gone.

It’s Playoff Jimmy’s time. He’s real. He’s here. And if he says that superhero doesn’t exist, he’s lying.