All the young players looked solid, the coaching change looks even better and apparently point guard Dennis Smith Jr. needed just three games off to contemplate.

On a giddy night at the Garden, Smith provided a surprise spark late in the first quarter and Mike Miller’s Knicks hammered the woebegone Hawks, 143-120, for their most dominant performance of the season.

It was the most points scored in regulation by the Knicks since 1980. After taking over at 4-18, Miller is now 3-3 since replacing the fired David Fizdale 12 days ago.

The Knicks had six players finish in double figures, led by rookie RJ Barrett’s season-high 27 points and Mitchell Robinson’s career-high 22. Marcus Morris added 22 and Kevin Knox and Julius Randle finished with 17 apiece.

Miller said he was most pleased the Knicks didn’t let the Hawks off the mat.

“There is a tendency when you get a lead sometimes to go away from what you’re trying to do and we stayed with it all the way through,’’ Miller said.

There was even playoff talk in the Knicks’ locker room, while the Hawks’ locker room remained closed for 40 minutes after the game.

Asked if the Knicks are making a statement to keep the team intact, Morris said, “That’s a tough question. And out my hands. That’s the goal, the playoffs.

“I’m not going to say we’re going to make the playoffs, but that’s what we’re fighting toward. If we continue to play like this and pull together, we have a great shot to do it. The last few games we’re really putting our foot on the gas.’’

It was Smith who put the pedal to the metal when the game was still close.

Miller, the interim coach, has seemed to press a lot of right buttons and now he’s done so with Smith.

After the 22-year-old point guard missed last Wednesday’s victory over Golden State with a migraine, Miller let Smith wallow on the bench the past two games. The Knicks were 2-1 in his absence — with a close road loss to Denver.

But Miller turned to Smith on Tuesday, and it paid off. He finished with eight points, five assists and five rebounds in 13 minutes.

With Smith in the game for all of it, the Knicks tore off on a 21-0 run in the first half to grab a resounding 77-53 intermission bulge.

The 77 points were the most they had scored in a half this season. The 41 points they notched in the first quarter were the most they have scored in a period all season.

“He was terrific,’’ Miller said of Smith, who was dusted off with 2:43 left in the first quarter after Elfrid Payton picked up his second foul. “The speed he came in [with] and brought at the end of the first and second, the plays he was able to make and the pressure he put on the defense was great for us.’

The Knicks were leading just 23-21 when Smith immediately went to work, hitting a 3-pointer. He picked up the team’s pace, driving frenetically downhill, finding Robinson for a dunk and Damyean Dotson for a couple of jumpers.

“This was our best overall game,’’ Smith said. “I just want to play. I was excited to check into the game. A lot of times we got a big lead and lost it. This time we carried it through.’’

Smith wound up a plus-17 in the first half. He blocked the dazzling Trae Young in the lane and picked up a steal soon after.

Some in the locker room believe the about-face is a lot about Miller.

“He’s a great guy,’’ Bobby Portis said. “Standup guy and has confidence in everyone he puts out there.”

Robinson pointed to the team meeting held hours before Fizdale was canned.

“We were pretty much tired of how the season was going,’’ Robinson said. “We decided we needed to make some changes.”