"They're probably the No. 1 team in the league, and they probably have the best duo in the league, too," Doncic said. "And we're in the Garden -- it's always a special game. You have to come 100 percent. If you're not, you're probably going to lose. It's a big game."
Doncic, in his fifth NBA season, enters Wednesday's game (7:30 p.m. ET, ESPN) as the NBA's leading scorer at 33.5 points per game while also averaging 9.1 rebounds, 8.1 assists and 1.9 steals.
Tatum and Brown, meanwhile, are the league's highest-scoring duo, averaging a combined 55.5 points per game -- just ahead of the 76ers' tandem of Joel Embiid and Tyrese Maxey (55.2) -- and earning Doncic's respect in the process.
"Just watching their game," Doncic said. "I think a lot of people can see that. I think the way they play. I know people try to separate them but they fit together, they went to the Finals last year, so I think those two are really great players."
Even after seeing their nine-game winning streak end Monday in Chicago against the Bulls, Boston still enters Wednesday night's game with the NBA's best record at 13-4, including a 6-1 record at TD Garden.
Boston has seen its success come from its high-powered offense, which sits second behind only the surprising Kings in offensive efficiency.
Doncic said another reason for his high praise of Boston is that the Celtics have managed to post the NBA's best record with center Robert Williams III missing the entire season so far following September knee surgery.
"They have one of the best records and they're missing I think a key guy, Williams III," Doncic said. "I am impressed by his game, have always liked his game. So with him being out, and them having this record, that's why I said that."
With 20% of the season in the books, Dallas sits eighth in the Western Conference with a 9-7 record -- but just 1.5 games out of first, showing how compact the West standings are this season.
That the Mavericks are 9-7 after losing Jalen Brunson in free agency can be put at the feet of Doncic, who has continued to develop into one of the league's outstanding talents and has taken his game to yet another level.
"It's a lot," Doncic said of the workload he has taken on this season. "You've got to be prepared physically. I think this summer helped me. Some games I'm really tired, because it's a lot of basketball, for two years I never stopped playing basketball, but I'm just happy to play basketball."