Knicks gave Tom Thibodeau the perfect birthday present

It was the perfect birthday gift for Tom Thibodeau.

Thibodeau is a proud New Englander, born in New Britain, Conn, a diehard Patriots’ fan who rooted early in his childhood for the Knicks before going green.

As he turned 63, Thibodeau didn’t get a big Tom Brady birthday cake but celebrated by returning to New England to destroy the Celtics with defense Sunday afternoon, 105-75.

This 30-point Boston matinee massacre ended his club’s five-game losing streak as his Knicks threw a perfect game at the Celtics at the fan-free TD Garden.

The forever intense first-year Knicks head coach even cracked a couple of smiles on Zoom in the postgame interview.

“You know I’m never happy,’’ Thibodeau said — with a grin. “I’m not happy, unless I’m miserable.’’

This was a thrilling afternoon in Beantown — best so far of his short tenure. The last time the Knicks battered Boston by at least 30 points, it was 1997 and Thibs was a young Knicks assistant.

“I actually grew up a Knick fan — my dad was a Knick fan,’’ Thibodeau added. “Then when I went to school in Boston [Salem State], it was in the mid-’80s so I became a Celtic fan. The irony of it all is I ended up working for both teams. If you grow up in Connecticut, it doesn’t get much better than that. Thrilled to be part of two storied organizations.”

True, the Eastern Conference-leading Celtics were missing superstar Jayson Tatum and had three games postponed last week because of COVID-19.

But the Celtics still took the Knicks lightly and they paid. Big time. They played as if their minds were on whether Brady, still a New England obsession, would get Tampa Bay to the NFC Championship game later Sunday.

The Knicks didn’t play badly Friday in their heartbreaking loss in Cleveland and took out their frustration on the Celtics.

“I told our players this: The way they’re practicing, the attitude, the approach and how they’re practicing has been a positive,’’ Thibodeau said. “I thought going to Cleveland, I thought we were ready to play. I thought we were terrific in the shootaround and we played well enough to win [Friday] on the road. We didn’t close out the game the way we would’ve liked. Then [Saturday] in practice I thought was terrific. As long as we’re doing the right things. I know we’ll improve and we’ll keep getting better.”

As promising a day as this was for the Knicks (6-8), it’s equally as good for the Brooklyn Dream Team. If the Celtics are their biggest road block to the NBA Finals, you can book Kevin Durant and James Harden’s trip this summer to Los Angeles.

The Knicks veterans and their two rookies, point guard Immanuel Quickley and forward Obi Toppin, played to their first-round stock, combining for 29 points on 12 of 20 shooting.

“If we keep playing like we did today, we’re going to win a lot of games,’’ said Toppin, who finally looked like a lottery pick in scoring 12 points and hitting 2 of 4 3-pinters.

Thibodeau’s club harassed the somnambulant Celtics into one of their worst outside-shooting performances in their storied history — 7 of 46 (15.2 percent) from the 3-point line. The Celtics couldn’t have hit water if they threw tea into Boston Harbor.

“Defense leads to offense,’’ said Knicks center Mitchell Robinson, who soared despite being hobbled. “The communication was there.”

Robinson entered the contest with a bruised heel, then took a nasty spill in the first half after blocking a 3-point shot. He hurt his knee but limped through the day on a football Sunday like a pigskin warrior, still an active dunk machine.

Meanwhile, Quickley delivered his usual jolt and got the disappointing Toppin going early with an alley-oop lob.

Thibodeau has stood his ground in keeping Quickley as lightning off the bench and Elfrid Patyon as starter. He was rewarded. There’s plenty of time to change up. Once he does, he can’t go back, or he’s David Fizdale.

Afterward, Thibodeau addressed the Quickley issue that has gripped social media enthusiasts. Payton’s defense is best used to set a tone early, Thibodeau said, and the Knicks smashed the Celtics from the opening tap. The Knicks coach said he would like to see Payton-Quickley as a pairing down the road.

“I love both guys — they’re different and bring different things to the team,’’ Thibodeau said. “It gives us great flexibility. Elfrid, when you look at his defense and size, a lot of these guards, particularly point guards in the NBA today, they’re a load to deal with. Elfrid has a good understanding how to defend them. He can play-make for us. And when Quickley comes in, he gives us a different look.”

Of course, it’s easier winning in this famous hall minus Boston’s rowdy crowd. TD Garden is the loudest building in the Eastern Conference. The Knicks made it as quiet as Sunday church.

Now it goes from Thibodeau’s birthday in Boston to the celebration of Martin Luther King Day at the Garden. Sunday will carry more significance on the court if the Knicks are as triumphant on MLK Day against Orlando.