BOSTON — In a week where the “Beat L.A.” hullabaloo was alive and well in the streets of Boston, the Celtics certainly did not provide the Hollywood finish Green Teamers were hoping for.

The Celtics outdid even themselves, doubling down on Thursday’s blown lead against the Los Angeles Lakers by blowing a 28-point first-half lead to the Los Angeles Clippers in a 123-112 loss Saturday night at TD Garden.

Boston scored a season-high 74 points in the first half, but followed it up with a season-low 38 points over the final two quarters as the air seemingly was completely removed from the Garden.

After winning 10-of-11, the Celtics how have dropped two straight as they turn to a critical Eastern Conference tilt against the Philadelphia 76ers on Tuesday.

After the game, Celtics coach Brad Stevens was asked if the recent trend of poor play in the third quarter is a part of the team’s identity.

“Well, if it is, we won’t last long, so at least you know, right?” said Stevens. “I’ve got to go back and look at, first and foremost, what I can do different to help. Our play out of the half at times this year has been really slow, and so that was again today. … You could kind of feel it going in the other direction and that’s it, and then we got pounded in the fourth.”

The Clippers outscored the Celtics 70-38 in the second half, including 42-26 in the fourth quarter. To make matters worse, the Celtics lost Kyrie Irving in the second quarter to a right knee sprain.

But Stevens continued to point to himself when it came to the Celtics’ second-half struggles.

“I think every year your trends change as the year goes on, both good and bad,” Stevens said. “It is disappointing to have 20-point leads in consecutive games and lose, that’s for sure.

“Again, I think I need to look at myself first and figure out what I can do to help that not happen. If that means we need to play different rotations, call different things, start differently in quarters than we are, whatever the case may be there’s an answer out there and we just have to find it.”

The Celtics have 26 games to find that answer. And they’ll need to find it quickly, as Tuesday’s matchup with the 76ers suddenly has become a must-win game.

Philly leads Boston by a half game for fourth place in the Eastern Conference standings.

Here are some other notes from Saturday’s Celtics-Clippers game:

— There was only one lead change Saturday, as the Clippers did not push in front until there was 6:02 left in the game.

— Daniel Theis continued to contribute solidly on offensive, going 4-for-4 from the field, including a 2-for-2 effort from beyond the arc. He is 20-of-45 from deep this season.

— Both sides’ leading scorers came off the bench, as the Clippers’ Montrezl Harrell had a game-high 21 points, while Gordon Hayward led the Celtics with 19. Four players off Boston’s bench finished in double-digit points as Hayward was joined by Terry Rozier (16), Jaylen Brown (12) and Theis (10).

Thumbnail photo via Bob DeChiara/USA TODAY Sports Images