Barrett stays red hot from behind arc in losing effort

If this continues, RJ Barrett will be in the 3-point shooting contest next All-Star Weekend — if not in the main event.

Barrett’s stark rise from beyond the 3-point stripe hit its climax in Boston, where he drilled all six of his 3 pointers, finishing with 29 points despite a 101-99 Knicks loss to the Celtics on Wednesday night at TD Garden.

Barrett finished with 29 points, shooting 10-for-14 overall. In his last 40 games, after a slow start, Barrett is shooting 45.9 percent from 3-point range (61-for-133). In the past five games, he shot 16-for-22.

While Barrett did commit a costly turnover down the stretch, leading to a Jaylen Brown fast-break layup, he bounced back to hit a game-tying 3-pointer soon after.

“I don’t know if I’m surprised because I see the time he’s put into it,’’ coach Tom Thibodeau said. “And when we’ve been home, he usually comes in every night to shoot and get extra shooting in. He’s really worked hard improving the shot and I think he’s gotten real comfortable behind the line. And I also think his teammates are also doing a good job looking for him. We’ve had good rim reads and a lot of spray-outs, so they’re goodrhythm 3s.”

During an up-and-down first season, when he was left off the two All-Rookie teams, Barrett shot just 31 percent from 3-point range. He’s now up to nearly 37 percent.

“I just work at it,’’ Barrett said. “Going to the gym at night, the more you put into the game, the more you get out.”

➤ In wake of the revelation made by Charles Oakley that the Garden offered to retire his No. 34 as a peace offering, Thibodeau said several players from the great 1990s teams should get the honor.

Thibodeau was an assistant coach on Jeff Van Gundy’s staff from 1996-2000 and stayed until 2003 after Van Gundy quit.

“In terms Oak and those guys, I love the ’90s teams so I’m for all those guys having their jerseys retired,’’ Thibodeau said.

Thibodeau was likely referring to 1990s stalwarts such as Oakley, John Starks, Allan Houston, Latrell Sprewell and Larry Johnson. Patrick Ewing already has No. 33 in the rafters.

The Knicks have been stingy when it comes to retiring their players’ numbers for posterity. Hanging in the Garden rafters are the numbers of the elite contributors who have on a Knicks championship and the guy considered the greatest player in their history — Ewing.

Oakley claimed that during conciliatory talks with the Knicks sometime after his 2017 ejection incident, team ownership offered to retire his number in a ceremony, but he declined, feeling it was to sell tickets.