OAKLAND, Calif. -- It's hard to determine exactly which moment in the fourth quarter of the Boston Celtics' 99-86 triumph over the Golden State Warriors made the least sense.

There was Boston's defense-ignited 15-0 run that saw the Celtics not only rally ahead but run away from a Warriors team that has been damn-near invincible at Oracle Arena in recent seasons. Then there was the sequence in which Boston, the 27th-ranked team in the league in rebound percentage, outhustled the Warriors for consecutive offensive rebounds while playing a bit of keep-away that ensured the Warriors would not rally back into the game.

But maybe nothing was as jarring as, after Isaiah Thomas pickpocketed an unsuspecting Draymond Green and was fouled in transition, Boston's All-Star point guard stepped to the free throw line and heard a hearty, "M-V-P!" chant inside Oracle.

Chants of "M-V-P" rained down on Isaiah Thomas toward the end of Boston's win over the Warriors. AP Photo/Ben Margot

Thomas had been serenaded with the same chant in Los Angeles last week where Boston expats packed Staples Center for a lopsided win over the Lakers. But to hear those three letters inside Oracle -- a spot where M-V-P is reserved for players like Stephen Curry and Kevin Durant, who actually have the hardware to back up those claims -- was inconceivable. Not since Lakers fans flocked north to cheer Kobe Bryant on this floor could locals remember such an occurrence.

"That's crazy. But, I mean, my teammates, my coaching staff put me in position to get those chants, so I'm just staying in the moment and I couldn't do it without those guys," said Thomas, putting on a clinic in how to say the right thing, especially in the aftermath of critical comments about his coach and teammates that drew national headlines.

"It is crazy though," Thomas added. "I don't want to miss free throws because they're saying that."

By his lofty standards, Thomas had a quiet night with 25 points on 7-of-20 shooting with three assists and three steals. But it's those thefts that hammer home the defensive tenacity with which Boston played. And it was that defense that keyed a Celtics' fourth-quarter run that the Warriors simply could not answer.

It's easy to forget given the outcome but there was a time when it seemed as if the Warriors were poised to take over the fourth quarter. When Andre Iguodala threaded a pass to Green for a loud slam with 7:19 to go, Curry had busted out his sideline binoculars and fans inside Oracle stood as if expecting their team to embark on a run.

But the opposite happened. A defensive lapse by Golden State allowed Kelly Olynyk -- maybe Boston's biggest hero after putting up 17 points on 7-of-9 shooting with five rebounds and five assists over 26 minutes -- to rumble free to the rim for a dunk. The Warriors got sloppy from there and Boston ratcheted up its defense, holding Golden State scoreless for more than three minutes.

The Warriors most certainly hurt themselves -- Curry dribbled the ball off his leg; Iguodala gave the ball away carelessly with Avery Bradley lurking -- but Boston was the aggressor in taking over the game. There was one sequence on Boston's run in which Bradley picked up Curry at midcourt and, when Curry lost his dribble trying to go behind his back, Olynyk swooped in to rip the ball away.

A fired-up Celtics squad, playing the sort of defense that everyone expected but has rarely been seen this season, were dripping with swagger as the run continued. So even after an offensive set sputtered initially, Thomas stepped up and drilled a 3-pointer with Iguodala in his mug.

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"We just made it tough on them," Thomas said. "Those are hell of a players over there -- Steph Curry, Klay Thompson -- we made it tough on them. I keep saying it but those three guys -- [Marcus] Smart, Avery and Jae Crowder -- they should be on one or two of those all-defensive teams because they make it tough on everybody each and every night. Kelly Olynyk played a hell of a game. Without him we probably wouldn't have won tonight. He gave us a boost off the bench."

The Celtics locker room wasn't quite as boisterous as it was a year ago when Boston ended Golden State's quest to go undefeated at home. But on a night when the Celtics risked sliding back to No. 3 in the East, this win resonated and left the team with obvious confidence.

In the span of eight days, the Celtics have beaten the two Finals combatants -- albeit with each team missing a key Kevin (Durant in Oakland; Love in Cleveland) -- and Boston's preferred starting five is now 19-6 when healthy.

Wednesday's fourth-quarter run reminded the Celtics what they are capable of when they are focused on the defensive end.

"We knew that our goal was to try to tire their guards down," Bradley said. "I think we did a great of job doing that. It showed because Klay Thompson, down the stretch, he missed a few shots. All credit to Marcus Smart, myself, and Jae, Isaiah, we were just trying to tire those guys down. I wanted to dig deep and make some big defensive plays for our team down the stretch. I was able to.

"That's what it's all about. That's what the Celtics are about, playing harder on the defensive end. Looking at Marcus Smart at the end of the game, and Jae, I could tell they wanted to win this game. I told Marcus, 'Bro, I'm going to make sure that I'm making [Curry or Thompson] take tough shots every single time down.' That was my mindset. And he told me the same thing."