BOSTON — It was a thumbs-down performance by the Knicks — and Julius Randle.

Evan Fournier was out with a bruised hip, so the Knicks needed Randle to be his All-Star self Saturday night against the Celtics, especially after the power forward created an unnecessary distraction for the team this week.

But Randle appeared to be pressing after putting himself in the spotlight, first giving a thumbs-down to Garden fans Thursday night in the first clash of the week against Boston and then saying he did it to signal the fans to “shut the f–k up.’’

Randle, getting worse as the game wore on, had no touch and was sloppy, at times failing to catch passes. And the Knicks were offensively inept as they were routed, 99-75, at TD Garden.

It was the fewest points the Knicks, who shot 36.7 percent, have scored since 2018.

Randle finished with 13 points, shooting 6-for-19 and 1-for-8 from 3-point range. He filled up the boxscore, committing six turnovers with six assists and 12 rebounds in 38 minutes.

“I don’t know if he was pressing,’’ Knicks coach Tom Thibodeau said. “They loaded up on him pretty good. That was anticipated. I thought he made a number of really good plays when the defense collapsed and he sprayed it out for good quality looks from 3.

“But to win on the road, you have to play for 48 minutes and we didn’t do that.’’

Randle was not made available for comment after the game and reporters are not permitted into locker rooms this season due to COVID-19 protocols.

Thibodeau had wanted Randle to put the controversy behind him after he apologized on Instagram and was fined $25,000 by the NBA for “egregious use of profane language.’’

Before the game, Thibodeau acknowledged Randle’s mistake.

“Like anyone, you have a bad day at work and you bounce back the next day,” the coach said. “Just make sure it’s not two days in a row.’’

There was no storybook bounce-back for Randle.

The Knicks also needed a big game from Alec Burks with Fournier out for just the second time this season. Fournier had scored 41 points in the Knicks’ buzzer-beating win Thursday and had dominated the Celtics all season. Burks, however, laid an egg, scoring eight points on 2-for-11 shooting.

The Knicks were also miserable from the free-throw line, shooting 6-for-15. RJ Barrett scored 19 points, but was 1-for-5 from the line.

“I think that’s just going to happen sometimes,’’ Barrett said. “There’s a lot of games during the season and, for some reason, today was that day.’’

The Knicks (19-21) and Celtics (19-21) now have the same record and have finished their season series at 2-2. They could meet in the play-in tournament, which will feature the seventh to 10th place teams in the Eastern Conference.

Without Fournier, Thibodeau started Immanuel Quickley and Burks in the backcourt.

“He’s a good player, good veteran player, even if he’s not scoring he’s creating space, which is vital for us,’’ Thibodeau said of Fournier. “But that being said we have more than enough to win with.’’

Boston’s Jaylen Brown (22 points) drilled a 3-pointer with one second left in the third quarter to send the Celtics into the final period with a 76-60 lead.

Randle didn’t score during a very poor third quarter in which he showed bad hands (or thumbs), bobbling passes, committing two turnovers and missing two straight 3-pointers.

“I liked the way we played in the first half,’’ Thibodeau said. “But in the first few minutes of the third we got back on our heels.’’

In the first half, Randle didn’t shoot well, but he drew double teams and recorded four assists. Still, his halftime line was bleak: 3-for-10, 1-for-5 from 3-point range and four turnovers, including two bad passes on consecutive possessions. One Randle delivery was intercepted, the other went out of bounds.

Randle’s backup, Obi Toppin, didn’t have anything going either. The fan favorite is regressing and had a regrettable performance.

Toppin was scoreless in nine minutes, had two of his driving attempts blocked and shot an airball that might have landed in Boston Harbor, where the tea fell with more frequency than the Knicks’ jump shots.