OAKLAND, Calif. -- MVP chants boomed off the walls of Oracle Arena as a point guard strode toward the free-throw line to ice a well-deserved victory against a team he could very well see again in the NBA Finals. Isaiah Thomas, not Steph Curry, buried both attempts, sending the contingent of Celtics, not Warriors, fans into a frenzy.

This wasn’t an ordinary Wednesday night at Oracle Arena. It wasn’t merely that the Warriors lost, 99-86, to the Celtics. That part -- given the Celtics’ rise to prominence in the East, the Warriors’ grueling schedule, and Kevin Durant’s injury -- wasn’t unexpected. It was the ending that felt eerie.

For three quarters, the Warriors and Celtics traded buckets. To that point, the game had all the makings of a typical Warriors victory.

Curry did Curry things, meaning he hit pull-up 3s, acrobatic layups, and a circus shot so crazy you should go watch it again. Klay Thompson dumped in 24 points. Andre Iguodala continued to show signs of reverse aging with a 4-of-5 shooting performance. Draymond Green added three blocks to his Defensive Player of the Year highlight reel. Heck, JaVale McGee banked in a running hook and Patrick McCaw actually took open shots when they presented themselves. A fan even won a car by outshooting Zaza Pachulia.

As the buzzer sounded to mark the end of the third quarter, Curry got Jaylen Brown into the air, dodged the rookie’s flailing body, and hoisted up a successful 3-pointer. Curry shared some words with Brown and the Warriors took their two-point advantage into the final frame.

It all fell apart. In that fourth quarter, the Warriors were outgunned by 15 points. They scored only 12 (TWELVE!) points. They turned the ball over eight times. Steve Kerr resorted to a Curry, Ian Clark, McCaw, Iguodala, and James Michael McAdoo lineup in a critical stretch that made the difference in the game. The Celtics ended the fourth quarter on a 21-5 run. They beat the Warriors in Oakland for a second successive season.

But that wasn’t even the weird part. This was: As the Celtics pulled away, the crowd serenaded Thomas with MVP chants. In Oakland. With Steph Curry on the court.

“Our fans were leaving,” Curry said. “We didn’t give them anything to cheer about. ... We can’t be sensitive about that.”

Steph’s right. It’s not a big deal -- the chants or the loss. The Celtics are a good team. The Warriors couldn’t buy a 3 or a free throw. It happens. The Warriors are banged up and tired.

Even Celtics coach Brad Stevens talked about it.

“I think this is one of the hardest games as an NBA team ... to come home for one game, which is what they are doing,” he said. “We might have caught them on a good scheduling night, but I thought our guys played with good poise and purpose.”

Stevens is also right. The Warriors returned for a one-game home stand after a five-game road trip. They leave Thursday for Friday and Saturday games in Minnesota and San Antonio, respectively. They’re in the middle of the most grueling portion of their season. This particular loss shouldn’t be held against the Warriors. And Kerr shouldn’t be ripped for his unsuccessful rotations. He was forced to use that odd lineup only because he can’t run his guys ragged, which he talked about after the game.

“We always give them [Green and Thompson] a rest at some point,” Kerr said. “There is no way we are going to let them play the whole quarter, especially with the stretch that we are on. That was a time where we had to get them out and give them a few minutes rest. Thing didn’t go well for those couple minutes.”

Yes, Kerr is right, too.

So, here’s what does matter: The Warriors have lost three of their past five games. They’re only 1½ games up on the Spurs for the top seed in the West. Durant, who sounded positive about his recovery before the game, might not return until the postseason. The Warriors, of course, already know all about how an untimely injury can derail a championship run.

At this moment, the Warriors are no longer invincible, which feels weird. That part might not necessarily matter -- after all, championships aren’t determined in March -- but that doesn’t mean it’s not worth noting. It has been a long damn time since the Warriors felt vulnerable.

The rest of the NBA should enjoy it while it lasts.