Rookie shooting guard RJ Barrett wanted to play the final summer league game, a consolation finale Saturday against Washington.

Knicks brass was leaning toward shutting him down after four games to avoid an injury, but Barrett felt there was more to gain.

Barrett is glad he played, finishing with a near triple-double in his most efficient outing in Las Vegas as the Knicks beat the Wizards, 103-87, at UNLV.

Shooting 7-of-13, Barrett posted his third straight double-double game. He got to the basket and notched 21 points, 10 assists, eight rebounds and just two turnovers.

“I love to play basketball — if I have opportunity to play, why would I sit out?’’ Barrett said on NBA TV.

His outside shooting needs work, though a late 3 put him at 2-of-4 from 3-point range. He finished the tournament at 7-of-30. But he redeemed himself after starting the summer league with two horrific outings.

Barrett finished averaging 15.6 points on 33.4 percent shooting.

“I felt I read the game well,’’ Barrett said of the finale.

Second-year man Mitchell Robinson and Kevin Knox also were surprise starters in Saturday’s consolation finale.

According to a source, Robinson and Knox wanted the chance to play another game with the new rookies, Barrett and Ignas Brazdeikis, who finished with 17 points on 7-of-11 shooting. Robinson was ruthless with 18 points, nine rebounds and three blocks. Undrafted Kenny Wooten, who likely will be at training camp, registered five blocks.

The Knicks were Vegas betting favorites to win the summer league because of their proven roster that featured six players who will see action on the Knicks this season — Allonzo Trier, Kadeem Allen (who is on a two-way contract), Knox, Robinson, No. 3-overall draft pick Barrett and Michigan second-rounder Brazdeikas.

But they stumbled to a 2-3 record. Trier, after scoring a team-high 21 points in the opener, got sick and missed the rest of summer league.

“We’ll keep building with him,’’ said Knicks summer-league coach Jud Buechler, who had indicated beforehand Barrett wouldn’t play the consolation game. “He learned from this summer league. He’ll watch film between now and training camp. He’ll have a much better idea what he needs to improve on.’’

Barrett has yet to decline an invitation from Team Canada for the World Cup, according to a source, but it would seem to be too much of a grind.

As for Barrett, his summer league received mixed reviews

“When you pick [at No.] 3, you’re trying to get an All-Star, and he definitely doesn’t look like that,’’ one NBA scout said. “But he looked like he’ll be an NBA player for a long time.’’

Former Knicks president Isiah Thomas, doing the call for NBA TV, said the summer league was “an R and D’’ experience for Barrett.

“When Steph Curry came into the league, he didn’t have the dribble he has now,’’ Thomas said. “He had to work at it. Barrett continues to work hard to get better.’’