Victor Wembanyama and Gregg Popovich accepted the San Antonio Spurs had been unable to live with an NBA championship contender after Sunday's 134-101 blowout loss to the Boston Celtics.

The league-leading Celtics improved to 26-6 with a dominant performance to round off 2023 at Frost Bank Center, extending their winning streak to six games.

Boston never trailed at any point as Jayson Tatum led six visiting players in double figures with his 25-point haul, while Jaylen Brown added 24 points on 9-of-13 shooting.

Rookie Wembanyama had 21 points and seven rebounds for the hosts, but it was not enough to stop them sliding to 5-27 with a seventh defeat in the space of eight games.

While Wembanyama said the Celtics were simply too good on the night, he believes the Spurs will have learned something from the defeat.

"I can feel that compared to the past years, they have something extra this year," Wembanyama said of Joe Mazzulla's Celtics team.

"Of course, it’s difficult to play against them and it is a good challenge. But I think we learned today."

San Antonio coach Popovich concurred, saying: "They are a championship-calibre team, that's what they are out there for, that's their goal, and they proved it once again.

"Joe does a great job with them. They've got good talent, obviously, all-star talent; and they've got the grit. 

"They've got the execution and are getting better all the time. That's a tough challenge at this particular time for our group."

Boston closed out the month of December with a 12-2 record and were able to rest their starters for much of the fourth quarter, having led by as many as 37 points at one stage. 

"We got stops," Mazzulla said. "I thought we were really good at doing both, protecting the paint and getting out to contest, which allowed us to get out in transition. 

"I think our secondary transition, we did a good job of recognising where the mismatch was and getting to it fast and playing together as a team through it."