Undermanned Knicks lose to No. 1 Celtics despite hot night from Jalen Brunson

It’s not supposed to look this easy. Not against the league’s best team.

Not against the NBA’s best defensive back court.

Certainly not as the focal point of a defensive scout with two key offensive weapons out due to injury.

Jalen Brunson turns high degree of difficulty shots into poetry in motion, and even a stingy Boston Celtics defensive backcourt couldn’t keep the Knicks All-Star out of the scoring column.

The Celtics coasted to a 116-102 victory at Madison Square Garden, but Brunson finished with a game-high 34 points on 12-of-25 shooting from the field and four-of-nine shooting from downtown. He posted these numbers despite being checked by Boston’s Jrue Holiday and Derrick White.

Both Holiday and White were named to NBA All-Defensive Teams at the end of last season. Holiday, Brunson’s primary defender, has been named First or Second Team All-Defense in five of the last six seasons.

Brunson’s performance, however, was encouraging, even if it resulted in a landslide defeat. If the Celtics can’t take the Knicks star out of a game when he’s the only star scorer on the floor, what’s going to happen when Julius Randle and OG Anunoby eventually make their return to the lineup?

The Knicks are hopeful the day will ultimately come when Randle (dislocated right shoulder) and Anunoby (right elbow surgery) are back on the floor with time to spare before the playoffs.

With both out, Brunson scored 19 points in the first half alone.

Yet without their entire starting frontcourt — Mitchell Robinson remains out after December ankle surgery — the Knicks were outmanned against a Celtics team with the best record in all of basketball.

The Knicks trailed by just four at the half but lost the third quarter, 35-26, and dug a hole as deep as 20.

“They have great defense. They have rim protection. Their rebounding has become elite,” said head coach Tom Thibodeau. “Offensively, they have a number of guys that can break you down off the dribble. They’re really skilled. They can spread you out. They shoot the three great. They play very efficiently. They take 50 threes a game. And they shoot it efficiently. Once they miss, those are long rebounds and they’re quick to the ball. You have to make sure you’re challenging shots and getting back to bodies.”

Josh Hart scored 16 points, and Donte DiVincenzo added 12 on four-of-eight shooting from downtown. Miles McBride (11 points) was the only other Knick to score in double figures.

Meanwhile, six Celtics scored 10 or more points, including Boston’s entire starting five, led by 30 from Jaylen Brown and 22 from former Knicks first-round pick Kristaps Porzingis, who was booed during pregame introductions.

Jayson Tatum finished with 19 points, six rebounds and six assists.

The Knicks have fallen to 0-4 against the Celtics this season, and because of the first-ever In-Season Tournament, they will play Boston a fifth time at the TD Garden on April 11.

“When you study it, their record tells you how good they are,” said Thibodeau. “You get into all their numbers. They’re strong on both sides of the ball. And then when you watch the film and match it up — and obviously, it’s a team where you have Tatum and Brown, and then you add in Derrick White and Holiday, and you add in Porzingis. It’s a team that doesn’t have many holes.”

If Randle and Anunoby are healthy by then, the Celtics will have much more to worry about than just Brunson, who has their number — even if Saturday’s matchup resulted in a Knicks loss.