When you watch a John Wall performance, you see all the point-guard possibilities that have been missing in New York for years. Wall didn’t shoot it so great until he had to — a game-sealing 3-pointer with 12 seconds left to go along with his 15 assists.

The Wizards rallied with a third-quarter domination to post a 110-107 Garden victory, and Wall’s dagger ended the Knicks’ charge to within three points in the final 20 seconds

If this season nets anything beyond a top-10 draft pick, maybe it can result in finding the Knicks a permanent point guard — whether it be Wall via blockbuster trade or Emmanuel Mudiay if he continues to play like he has.

Who ever figured it would be about Mudiay versus Wall in the season’s 25th game while reputed defensive stopper Frank Ntilikina sat all night for the second straight game and Trey Burke missed it with a sprained knee?

This wasn’t Mudiay’s best night, but he was a part of the Knicks’ late 12-0 surge and finished with 16 points and four assists — a plus-4 in the loss.

Mudiay turned on the jets in the final period, especially late, when he darted on a fast break, got fouled, made two free throws and got the Knicks within five with 1:02 left. After a Wizards miss, Mudiay broke out in the open court and fed Noah Vonleh for a fast-break deuce, and the Knicks were down three.

It’s been a rather stunning 11-game run for Mudiay as a starter. He had flashes in the first half draining a corner 3 — after missing his first five shots — in the final seconds of the half that pushed the Knicks’ lead to 11. He got to the rim early in the fourth for two easy driving buckets. He was a plus-15 running the show in the opening half.

Some in the league believe the Knicks are stocking up their young assets and will make a major play for Wall if he becomes available. The Wizards (9-14) were said to be ready to break it up after their disastrous start. It would have to be a three-team deal with the Knicks throwing in Ntilikina, Dotson, Courtney Lee (for cap purposes), a 2020 first-round and second-round pick.

Or they can wait to see if Mudiay, all of 22, is turning into the real deal.

Last March 5 at a Portland college practice gym, Mudiay celebrated his birthday. One Knicks player said: “You’re 22? Feels like you’ve been in the league forever.’’

In fact, if Mudiay used up all four years of his college eligibility, he would be a senior this season.

Mudiay is now the unquestioned and surprising leader in the Knicks’ three-man point-guard derby. Starting point guard of the present, maybe the future. It’s a stunning turnabout.

It’s too early, but no longer crazy to imagine. If the Knicks feel they are out of the superstar free-agent market (Kevin Durant, Kyrie Irving, Kawhi Leonard, even Kemba Walker), then it could happen. By far, point guard is their most egregious weakness.

Mudiay’s cap hold is $12 million. Factoring in cap holds on Kristaps Porzingis, Noah Vonleh, Allonzo Trier and an expected top-10 pick, the Knicks would have $21 million in cap space, according to ESPN cap guru Bobby Marks.

That could be rolled over to 2020 or they could go after a second-tier free agent — even Bucks point guard Eric Bledsoe, whom the Knicks’ brass likes. By keeping a cap hold on Mudiay, they can re-sign him and go over the cap.

Three weeks ago on a cold morning in Oklahoma City, David Fizdale made the announcement that Mudiay would be his new starter. The Knicks coach had begun the season with Burke, then veered to Ntilikina after five games. Fizdale tried a third time and it became the charm. Fizdale became the Mudiay whisperer — reaching him like no coach has reached him before.

On Saturday, in the season’s best victory versus Milwaukee, Ntilikina was a coach’s decision, and Mudiay was brilliant with a season-high 28 points, seven in overtime. The seventh pick of the 2015 draft has averaged 14.1 points and 2.9 assists since being named starter 11 games ago.

When the season began, Mudiay seemed a lottery-bust afterthought. He missed the first six games with an ankle injury. Insiders will tell you it is the two “C’s” that have Mudiay’s star illuminating: confidence and conditioning. Larry Brown told The Post in late April that conditioning has been the one thing holding Mudiay back.

Even in the Milwaukee game, Fizdale saw signs of Mudiay tiring in the fourth quarter, took him out, and he found a second wind in OT. Fizdale said Mudiay was in terrific shape in training camp but lost that edge after his ankle sprain. He’s been doing sprints with Kevin Knox after practice.

Mudiay nearly played for Brown at SMU but high school eligibility issues surfaced and he chose the money and China. Knicks general manager Scott Perry consulted with Brown after he made the February trade-deadline deal. Perry thinks Mudiay’s career would have been different had he played one season under Brown.

One year ago, Mudiay was miserable — refusing to talk to Denver media. Now he can’t stop doing his talking on the court.