SAN FRANCISCO >> Much has changed since the Warriors came into Boston and beat the defending champions in their own arena on Nov. 6.

De’Anthony Melton tore his ACL and got replaced by Dennis Schroder. Jonathan Kuminga rose, then fell to a significant ankle sprain. The win was part of a 12-3 start, and since the Warriors became the first team ever to open a season that hot and dip below .500 at any point thereafter. News cycles swirled around the existential questions engulfing this iteration of a dynastic era.

The Celtics haven’t even been playing well of late, going through the typical post-championship malaise. They still showed how much juice has squeezed out of the Warriors in the past couple months.

The Celtics shut down Golden State’s fledgling, short-handed offense in a commanding 125-85 victory over the Warriors at Chase Center. Boston had its championship starting five while Golden State was missing Draymond Green, Kuminga and Brandin Podziemski. The extreme talent disparity was apparent as the Warriors trailed by 45 and didn’t own a lead after the first quarter.

“They are the defending champs, so they’re coming in with a level of confidence and swagger about them,” Steph Curry said after the blowout loss. “Exact opposite of what we have right now.”

Golden State (21-21) scored a season-low 85 points in their second-largest margin of defeat this year. The 40-point deficit is the fourth-worst home loss in franchise history and worst in the Steve Kerr era. The Warriors shot 34.8% from the floor and 26.4% from deep, numbers made to look better than they were by garbage time.

“Whenever you lose by that much, it’s unsettling,” Kevon Looney said postgame.

The Warriors have insisted they’re not waving the white flag on the season, even if their activity leading up to the Feb. 6 trade deadline is as quiet as they’ve forecasted. But in this beaten and battered state, simply competing against competent teams is going to be difficult.

“You got to believe that you have enough to win in a given night,” Curry said. “You have to believe that we’re a team that can find a way to execute on both ends of the floor. It’s a mentality thing before a physical thing.”

The absence of Green — out at least the next week with a mild left calf strain — along with Kuminga’s sprained ankle opened the door for Moses Moody (13 points, 5 rebounds, 5 assists) to play more power forward. It’s where the Warriors have liked Moody best for years, Kerr said, because of his defensive switchability and perimeter shooting.

In Moody’s first minutes, he stood up Kristaps Porzingis in the post despite giving up 8 inches of height. Then he drove down the lane and found Looney for an assist.

The defensive stop was notable. The Warriors appeared to switch on defense more than usual, likely because of Green’s injury. That left mismatches for the Celtics to pick at.

Boston targeted switches, either against Curry or with a wing sizing up Trayce Jackson-Davis on the perimeter. While that strategy made sense, it may have taken Boston out of its go-to offense at times.

But as Golden State’s defense held up, its offense didn’t reward it.

“I thought we played a really good first quarter,” Kerr said postgame. “Late in the quarter, we had seven assists, no turnovers. We were getting a lot of good looks, competing defensively, but the ball wasn’t going in.”

That Looney jumper was the only Warriors field goal in the last 5:20 of the first quarter. Curry sat, and the bench unit burped up 10-1 Celtics run. Buddy Hield, who went 1 for 3 at the foul line, was particularly ineffective in that key stretch.

The Warriors went 7:32 of game time without a field goal. They missed 14 of their first 15 3-point attempts, including several clean looks.

Schroder’s 3-poibnter gave the Warriors eight points in 11 game minutes. Even a miniature Curry flurry at the end of the half didn’t do much as the Warriors went 3 for 24 (12.5%) from behind the arc in the first half and fell behind by 15.

One of the worst offenses in the league for almost two months now, the Warriors scored just 39 first-half points. Andrew Wiggins missed his first seven field-goal attempts after a few high-volume scoring games.

The wholesale offensive ineptitude made the second half a glorified scrimmage. The Celtics got whatever they wanted in the third quarter, winning the period 43-24.

Boston relentlessly attacked Curry on defense, aiming to tire him. Curry played through a mild ankle sprain and has had his thumb wrapped for weeks now. That’s in addition to the bilateral knee tendinitis that has popped up throughout the season.

When Curry had the ball, the Celtics zoned up in help defense behind the initial action or double-teamed him, daring anyone but Curry (18 points on 6-for-16 shooting) to beat them. The multifaceted game plan worked to a T.

Those other scorers the Celtics chose not to worry about? Wiggins finished 1 for 11 with four points. Schroder, after some early production, registered a -29 plus-minus. Hield was invisible.

The game got so out of hand, Curry sat for the entire fourth quarter, often with a towel draped over his head. They started the fourth quarter with Hield, Pat Spencer, Lindy Waters III, Gui Santos, and Quinten Post and fans filed out of the arena with 10 minutes left.

Earlier in the season, the Warriors beat the Celtics by coming at them in waves. Just about everything they used to have going for them has dried up since.

“These are demoralizing,” Kerr said. “The most important thing to me is for our guys to forget this one. They have a day off (today), then be ready to roll in Sacramento.”