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SAN FRANCISCO -- Klay Thompson's washed. Jordan Poole was a one-year wonder. The defense isn't the same. The young guys just aren't ready. The rotation is a mess.

We've all heard some version of these storylines as the Golden State Warriors plodded along to a .500 record through the first six weeks of the season, seemingly nursing a lingering hangover from last June's championship run. And on Saturday night they were scheduled to run into a buzzsaw, a 21-5 Boston Celtics team that was leading the league in wins, offensive efficiency and net rating. The meeting was the first since Golden State beat Boston in last season's NBA Finals. A Celtics win, and they'd be hearing the "changing of the guard" narrative every day until their next matchup in Boston in mid-January.

Instead, in front of a buzzy Chase Center crowd that seemed to understand the stakes, the Warriors showed exactly why the early-season concerns ultimately don't mean much, as they cruised to a 123-107 win in which they never trailed after the six-minute mark of the first quarter. Every Boston run was met with fevered resistance from a Warriors group that, despite its flaws, has only lost two home games so far this season.

"I thought we needed a game like that," Warriors head coach Steve Kerr said after the win. "We've been a little bit stuck in the mud, and it feels like we've gotten better over the last few weeks but not a whole lot to show for it. So this was a an important win for us."

The glitzy story was Klay Thompson, who was electric from the jump. Left for dead at times this season by both the fans and media, Thompson finished with 34 points on 14-for-26 shooting, including 4-for-11 from the 3-point line. His fellow Splash Brother Stephen Curry was steadily breathtaking, exuding the precise combination of patience and bravado that has made him impossible to defend for the better part of a decade. All told, he ended up with 32 points on 21 shots and was a game-best plus-20 in his minutes. Ho hum. He also added a wrinkle to one of his signature look-away 3-pointers, asking the fans if it went in after beating the first-quarter buzzer.

As exciting as Curry and Thompson's offense was, Golden State's defense was the story of the game. The Warriors entered Saturday allowing 112.7 points per 100 possessions, good for a bottom-10 league ranking and a far cry from the 106.6 they gave up last season. With their best perimeter defender, Andrew Wiggins, missing the game due to an adductor injury, Kerr elected to start Poole in his spot. That left either Thompson or Curry to cover one member of Boston's dynamic duo, Jaylen Brown and Jayson Tatum.

Call it instinct, but Kerr chose Thompson, whose defensive capabilities have diminished from his previous All-NBA standard, to begin the game guarding Tatum -- perhaps the leading MVP candidate at this point in the season. Thompson set the tone immediately by pinning Tatum's very first shot attempt against the glass, preventing what would have otherwise been an easy layup. Thompson said he hasn't had that type of block in at least four years, so it felt "amazing," and he's going to rewatch the film.

"I love to compete on both sides of the ball, and Tatum and Brown are two of the better one-on-one players in the league," Thompson said after the game. "It's not easy when you're tasked with chasing those guys, but it's what you cherish as competitors -- playing against the best of the best. There's really nothing better."

Thompson guarded Tatum and Brown at various times throughout the game, while Draymond Green and emerging second-year forward Jonathan Kuminga, one of the Warriors' brightest spots of late, shared the responsibility. The result was a 6-for-21 shooting night from Tatum, including 2 for 9 from beyond the 3-point line. The Warriors will be the first to admit that the All-NBA forward missed some shots he usually makes, but the energy and effort was there to run him and Boston's other league-leading 3-point shooters off the line.

After dropping out of the rotation early in the season, Kuminga is developing into one of the Warriors' most consistent defenders, which has earned the trust of the coaching staff. It's a learning process, and going up against two of the league's best scorers can only hasten the improvement.

"Especially if I get more matchups with [Tatum and Brown], knowing that they like to go left or right, doing different moves on the floor, I think it was good for me," Kuminga said. "It's part of my growth that when I go back and watch film, and just know what I need to do better."

The Celtics entered Saturday's game with an offensive rating of 119.9, the best in NBA history, while boasting league-best marks in 3-pointers per game (16.6) and 3-point accuracy (40 percent). The Warriors held them to 107 points and 12-for-40 (30 percent) shooting from deep. Obviously teams miss shots, but Kerr thought Golden State's defensive tenacity caused problems for Boston.

"Our guys did a good job of playing with a lot of energy and trying to challenge," Kerr said. "We did a pretty good job of keeping them from getting into a good rhythm. But it's one game, and it wasn't their best night for sure. But it was a good night for us."

Now the task is to string more of these two-way efforts together, a tall task given the 14-13 Warriors' next six games will come on the road, bookended with matchups against Giannis Antetokounmpo's Milwaukee Bucks and the suddenly red-hot Brooklyn Nets, led by a familiar face in Kevin Durant. Golden State won't play another home game until Christmas Day against the Memphis Grizzlies.

But that's the thing with the Warriors. Even if they go winless on the road trip, Saturday's win over the league's best team shows what they have in the tank, and could potentially be waiting for opponents when the postseason arrives.

"These games matter in the sense of preparing yourself mentally for what playoff basketball is like, and figuring out how to build as much of a presence in those type of games as possible," Curry said of Saturday's win over the Celtics. "You also have to assess the team as it stands, like what do we have out there? How do the matchups go? Kind of foreshadow what a playoff series will look like. So it was a good feeling tonight to win a game like that."