Celtics Banner No. 18 a group effor

Apparently the Boston Celtics do come with an on-off switch.

Sorry; please excuse the disrespect.

Make that the World Champion Boston Celtics.

After an historically lopsided loss in Game 4, the Celtics flipped the switch for Game 5 at the Garden.

The Mavericks were toast before the opening tip. Dallas wore the look of a little brother who suddenly realizes big brother has no patience for any more nonsense.

Luka Doncic? Done.

Kyrie Irving? Done.

Jason Kidd and the rest of his starry-eyed crew?

Done and done.

The 2023-24 Celtics made it their game the way they made their previous 79 wins their own. They played defense.

Jaylen Brown didn’t receive the Finals MVP award for his shooting touch; he won it for playing defense with an aggression that would have earned him a smile from Bill Russell, for whom that award is named.

He dogged the Mavericks in such a way that Doncic, reputed to the most talented player in the series, melted into a puddle of tears.

As for Irving, the Mavs guard with with fastest tongue in the West, ran down to the Celtics bench and offered hugs for Brown, Jayson Tatum, Kristaps Porzingis and anyone else he recognized.

When he tried to hug Joe Mazzulla, the Celtics coach reacted with the glare of a man who silently wished he could toss Irving into the crowd and let the fans deal with him.

Not that the Garden crowd hadn’t already crawled inside Irving’s head the moment they saw him. They stayed there throughout, showering him with a cascade of nastiness.

There must be a rogue leprechaun jumping around in Irving’s noggin. Or he so revels the spotlight that he is willing to bear the brunt of rhetorical mugging to bask in its searing glow.

Tatum, understanding his jump shots’ nagging unreliability, did his work in the lane and creating situations in which his fellow Celtics could do some scoring.

And then there is Payton Pritchard, the designated half-court shooting artist. As the clock neared halftime, for the second time in the series Pritchard launched a 3-pointer that kissed the backboard dropped through.

Doncic tried to disrupt Pritchard with a 6-inch vertical leap and arms extended. His futility was palpable.

The big guy may have figured out that stars are enhanced by playing at both ends of the floor. Now he just needs to become a sound defensive player.

Pritchard’s second long-range buzzer-beater of the series quelled what passed for a Dallas surge and restored a 21-point lead at halftime. It also reignited the crowd.

With their 18th championship banner already being stitched, the Celtics had some fun in the second half, while still playing rabid defense.

As for the MVP honors, Brown made sure to mention Tatum in his post-game speech. His long-term partner in crime, as Brown put it.

One man’s MVP was Derrick White, who earned the Tommy Point of all Tommy Points. Diving for a loose ball, White had his face driven into the parquet by Dallas’ Dereck Lively II.

White endured a chipped front tooth. Had Mazzulla tried to keep White from returning to the floor the coach may have ended up on the floor.

“I’ll lose all my teeth for a championship,” White said during the post-game madness.

That surely would inspire another Bill Russell smile.