Their mojo.

When they left Boston late Wednesday night, they were undeniably the best and hottest team in the NBA. But it's taken just two days out here for the Celts to lose their air of invincibility. Not to mention two games.

One night after seeing their 19-game winning streak slip into the Pacific somewhere around Los Angeles, the Celtics watched an 11-point lead with 13 minutes remaining dissolve into a 99-89 loss to Golden State.

That would be the now 9-22 Warriors.

If you're keeping track, the Celts have accomplished in two games what it took them the first 29 to do - namely to lose twice.

To fall here, the Celtics needed a major collapse. Allowing the Warriors 35 points in the last quarter certainly would qualify. Stephen Jackson had 15 points in the period while the C's were making just 6-of-20 shots.

``I was worried at halftime when I saw we were shooting 56 percent, they were shooting 39 and it was just a 12-point game (51-39),'' C's coach Doc Rivers said. ``I was really concerned with the game. My whole thought was if it got close we had no legs. I could see that.''

And as was the case against the Lakers, turnovers were again a major problem. The Celtics gave the rock up 23 times last night, leading to 27 Golden State points.

It all happened without Kendrick Perkins, who was a late scratch with a left shoulder strain suffered in the first quarter of Thursday's loss in LA. Leon Powe was the territorial pick to start in Perkins' place, and the Oakland native and Cal product celebrated his familiarity with 12 points and seven rebounds in 25 minutes.

But things were crumbling all around him by the end.

The Celtics really should have put the Warriors out of their misery in the third quarter. The only thing stopping them was . . . them. It took the C's nearly half the period to miss a shot, but getting that far in the process seemed to be a problem as they turned the ball over five times in less than five minutes.

The Warriors got 12 points from eight Celtics turnovers in the period and were within a reasonable 72-64 entering the final frame. But beginning with a Marco Belinelli trey at the end of the third quarter, the Warriors fashioned an 18-6 run that took them all the way back from as many as 14 down to a 79-78 lead.

``I just didn't think we could get control of it with our defense,'' said Paul Pierce, the C's top man with 21 points. ``We allowed too much dribble penetration. That's just not the way we play defense. I thought we gambled a lot and it opened up their 3-point game.''

The margin got to 87-78 before the C's spoke up with a Kevin Garnett three-point play. But they couldn't steer out of this skid. ``I thought the turning point was when we had to sub Kevin out (late in the third quarter),'' Rivers said. ``There was a five-minute stretch where we couldn't hold the lead. Once they start making shots it's tough to turn them off. And we couldn't make anything.''

Perkins' absence is expected to be a one-game deal - and more comforting to the Celts, it does not appear to be directly related to the dislocated shoulder he suffered in Game 4 of the Finals against the Lakers that required surgery over the summer. Perkins took a hit as Luke Walton was blocking his shot Thursday, and he thought after the game he'd have no problem playing here. But the shoulder was sore when he awoke.

``It kind of caught me off-guard,'' Rivers said of the injury. ``I knew he hurt it (Thursday) night and I knew he'd get treatment this afternoon, but I just assumed that he would play.''

- sbulpett@bostonherald.com