The Nuggets missed the chance to close the gap on Oklahoma City after losing a thrilling duel 131-130 against the Mavericks on the road in Texas.
Mavericks prodigy Cooper Flagg once again stole the show, with the gifted 19-year-old No.1 draft pick scoring a game-high 33 points with nine rebounds and nine assists.
Flagg's performance was backed by 31 points from Anthony Davis as Dallas outdueled Nuggets duo Nikola Jokic and Jamal Murray, who accounted for 60 Denver points.
The Nuggets almost snatched victory at the buzzer, but Peyton Watson's wide-open three-point attempt bounced out after hitting the rim.
"We're just coming together, trying to have each other's backs," Flagg said. "Obviously Jamal and (Jokic) had it going - so we were just trying to take those guys away and make somebody else beat us."
Dallas improved to 12-19 while the Nuggets slipped to 21-8 in the West.
Flagg took encouragement from another hard-fought win by the Mavs, who last week took down the Eastern Conference-leading Detroit Pistons.
"We're learning from all of these experiences," Flagg said. "You know we've been in a lot of really close games, so just trying to take stuff from those games and learn from it and get better."
Ten days after eliminating the Thunder from the NBA Cup semi-finals, the Spurs once again proved too strong for the Western Conference leaders as they powered to their seventh straight victory in San Antonio, beating OKC 130-110.
Starting shooting guard Stephon Castle finished with 24 points, including four three-pointers, but the key contribution came from Johnson, who added 25 off the bench, including five threes.
The Thunder fell to 26-4 after the loss, while the Spurs improved to 22-7 to stay in second place in the West.
San Antonio's Victor Wembanyama finished with 12 points while reigning NBA Most Valuable Player Shai Gilgeous-Alexander led the Thunder, scoring with 33 points.
"It shows how serious we are - we've got the same aspirations that they have, we just want to come out and compete every time we play them," said Castle, who poured in 10 of his 24 points during the fourth quarter in which the Spurs outscored the Thunder 43-28.
Elsewhere on Tuesday, Anthony Edwards rattled in 38 points as the Minnesota Timberwolves took down the New York Knicks 115-104 in Minneapolis.
Edwards knocked down four three-pointers while teammate Julius Randle added 25 points as the Wolves eclipsed a 40-point performance from Karl-Anthony Towns.
Knicks star Jalen Brunson, who scored 47 points in Sunday's win over Miami, missed the game with a right ankle problem.