The Miami Heat ended Boston's nine-game NBA winning streak with a 124-103 victory that pushed the reigning champion Celtics further behind Eastern Conference leaders Cleveland - who rallied to beat New York on Wednesday.
Tyler Herro scored 25 points to lead seven players to score in double figures for the Heat, who fought off a late Celtics surge to notch a sixth straight victory.
Boston connected on just 37.2 percent of their shots in the first half in the face of stout Miami defense and Miami pushed their lead to 22 points early in the third quarter.
The Celtics, led by 24 points from Jaylen Brown, cut the deficit to three, but Miami had pushed it back to 10 entering the fourth quarter. After the Celtics pulled within four early in the final frame the Heat relentlessly pulled away again.
The victory solidified Miami's position in the Eastern Conference play-in while the Celtics fell five games behind the Cavaliers atop the conference with six games left in the regular season.
Donovan Mitchell scored 27 points and Jarrett Allen added 21 on impressive 10-of-11 shooting for the Cavs, who rallied from an early 15-point deficit to beat the Knicks 124-105 in Cleveland.
The Knicks, third in the East, were again without top scoring threat Jalen Brunson, who missed his 14th game with a sprained ankle.
Even without him, the Knicks were on a three-game winning streak, but after leading by as many as 15 points on the way to a 60-53 half-time lead, New York ran out of gas.
New York's OG Anunoby made five of six from three-point range on the way to 19 first-half points but scored just four in the second half.
Karl-Anthony Towns led the Knicks with 25 points and 13 rebounds, but after closing the first half on a 10-2 scoring run the Cavaliers out-scored the Knicks 38-25 in the third quarter to seize control.
"We didn't put our best foot forward at the start," Mitchell said. "We came out kind of sloppy ... For the rest of the game, the last three quarters, we did what we were supposed to do."
Mitchell added six rebounds, five assists and three of Cleveland's five blocked shots.
"Just trying to do everything I can to win," he said.
The Knicks remained three games ahead of the fourth-placed Indiana Pacers, who were fueled by 22 points and 10 assists from Tyrese Haliburton in a 110-105 victory over the Charlotte Hornets.
In the Western Conference, the Oklahoma City Thunder took their winning streak to 11 games with a 119-103 home victory over the Detroit Pistons.
Most Valuable Player candidate Shai Gilgeous-Alexander scored 33 points, Jalen Williams added 23 and Chet Holmgren chipped in 22 points and 11 rebounds for the Thunder, who are assured of the top seed in the West.
Behind them, the Houston Rockets clinched a playoff spot in emphatic style, beating the league-worst Utah Jazz 143-105.
The Rockets are three games ahead of the Los Angeles Lakers and Denver Nuggets - who fell 113-106 to the San Antonio Spurs as Denver coach Mike Malone rested all five of his regular starters one day after their double overtime loss to the Minnesota Timberwolves.
The absentees included reigning MVP Nikola Jokic, who scored 61 points and played 53 minutes in Tuesday's defeat but has been nursing elbow and ankle injuries.
In Dallas, Anthony Davis took an elbow to the eye early but came back to drive for the game-winner with 3.4 seconds left in the Mavericks' 120-118 victory over the Hawks.
Davis, who suffered a cut over his right eye when teammate Daniel Gafford accidentally elbowed him, scored a game-high 34 points with 15 rebounds and the Mavs gained a much-needed win as they battle for a play-in tournament berth.
The top six finishers in each conference qualify automatically for the playoffs, while teams placed seventh to 10th will battle through the play-in tournament for the final two spots.
