Garnett made his points loud and clear last night as the Celtics held off the Los Angeles Clippers, 95-89, their second successive victory after a 4-8 slump dating to Dec. 25. Garnett harried the Clippers as they attempted to rally in the final minute, raising the intensity level of his teammates and the decibel level of their communication.

“I think it’s just the spirit of being back,’’ guard Rajon Rondo said of Garnett’s return. “It’s a whole other ballgame.’’

The Celtics (29-13) trailed by as many as 9 points during an opening half that was delayed several minutes while condensation was mopped off the court. They closed the half with a 10-4 run. The Celtics started the third quarter with a 15-6 run, Rondo’s drive making it 58-50 with 5:52 remaining.

The Clippers pulled within 64-59 on Rasual Butler’s second-chance 3-pointer with 1:23 to go. But the Celtics outscored the Clippers, 21-15, in the quarter, their best third-quarter margin since Dec. 22 (35-20), a 103-94 win over Indiana. Since that game, the Celtics had not outscored an opponent by more than 4 points (34-30 over Toronto) in the third quarter.

In fact, the Celtics celebrated their third-quarter performance Friday night, playing Portland even, 19-19, then eking out a 98-95 overtime victory to barely avoid a four-game losing streak.

“Last game, it didn’t seem like we lost three games in a row,’’ Rondo said of the Celtics’ rejuvenation. “It’s something we’re definitely feeling a lot better about, our defensive presence.’’

Garnett went out with a hyperextended knee in a Dec. 27 visit to Los Angeles, the Celtics losing, 92-90, to the Clippers.

“That was the game we noticed he was injured,’’ coach Doc Rivers said.

This time, Garnett seemed quite healthy, providing the foundation for the Celtics’ defense. This time, Rondo (16 points) concentrated on fronting Baron Davis, and Kendrick Perkins played physical against Chris Kaman. That defensive focus paid off in the second half.

The Celtics seemed to have the situation under control as Tony Allen’s steal and layup increased the lead to 71-61 with 10:49 remaining. But the Celtics would convert only once more from the floor over the next 5:37.

Ricky Davis’s free throw cut the Clippers’ deficit to 71-63, then Craig Smith scored the next 11 LA points. Smith made it 77-73, then Perkins missed two foul shots; but Ray Allen (15 points) chased down the rebound and fed Paul Pierce (22 points) for a 3-pointer for a 7-point advantage with 5:12 remaining.

A Garnett foul shot upped it to 84-76 with 2:06 to go. The Celtics were going for a double-digit advantage as Pierce took a jumper, but Butler blocked the shot from behind.

But that’s when Garnett displayed his defensive instincts. First, Garnett got back in time to stop Baron Davis, the Clippers retaining possession and calling a timeout. The Clippers then set up an in-bounds play similar to the one that beat the Celtics at the buzzer in December. This time, Butler stepped out of bounds under pressure from Garnett.

The Celtics made 9 of 10 foul shots over the last 34 seconds.

Garnett might not be completely recovered - he scored 17 points, but had only 2 rebounds, no blocked shots, and seemed exhausted late in the third quarter. But his mobility, plus his ability to make others perform better, was on display when it counted during crunch time.

“I think that I am just talking, I am trying to bring a certain amount of defense, and a certain amount of energy to the defensive end,’’ Garnett said. “Two rebounds is not enough for me, I know that I am a better rebounder than that. It’s timing - I am not perfect. I will get better at that as the year goes on. But, for the most part, I am playing my lane and doing what I am supposed to do, which is get Rajon open, get Paul open, get Ray Allen open, get guys like Perk and Rasheed [Wallace] easy shots, and at the same time, be a post presence. That is where I am right now - this is my mind-set.’’