Miami - Jaylen Brown scored 17 points as the Boston Celtics stunned the high-flying Miami Heat to complete back-to-back road wins in Florida on Thursday.
The Celtics, fresh from a 92-79 win over Orlando on Wednesday, were convincing 95-78 winners over Miami after a dominant first-half display.
The upset loss was Miami's first home defeat of the season, jolting a team who had impressed en route to building a 6-1 record to lead the Eastern Conference.
Boston by contrast have struggled through the opening weeks of the season, conceding an average of 115 points per game prior to Thursday's win.
But it was a hard-nosed defensive effort that stymied Miami's potent offense on Thursday to set up the win.
In-form Miami ace Tyler Herro was restricted to just six points from the bench, while Kyle Lowry also finished with six points before limping off with a sprained left ankle in the third quarter.
Jimmy Butler led Miami's scoring with 20 points while Duncan Robinson had 16 points.
"Everyone's locked in one through five," Celtics forward Romeo Langford said.
"We guard through the whole possession. We limited those guys on second-chance points and guarded them individually."
Boston meanwhile had six players in double figures, and could even allow for an off night from Jayson Tatum, who did not get on the board until the fourth quarter. Tatum finished with 10 points.
After Miami took the first quarter 24-18, Boston erupted in the second quarter to outscore the Heat 33-9.
That gave the Celtics a 51-33 half-time advantage from which the Heat never recovered.
"Defensively, you do have to give Boston credit," Miami coach Erik Spoelstra said afterwards. "That's probably as poorly as we've played offensively all season, including preseason and training camp.
"But those nights are going to happen. Sometimes it's going to be ugly offensively."
Miami's defeat allowed the Philadelphia 76ers to leapfrog them into first place at the top of the Eastern Conference.
The Sixers improved to 7-2 with a 109-98 win over the hapless Detroit Pistons in the Motor City on Thursday.
Detroit, chasing only their second win of the season, led 66-63 at half-time but faded badly after the half-time as Philadelphia pulled clear.
The Sixers outscored the Pistons 23-16 in both the third and fourth quarters to ease to victory.
Seth Curry, who had led the Sixers to defeat over the Chicago Bulls on Wednesday, was once again on form, leading the scorers with 23 points.
Tyrese Maxey had 20 points while Joel Embiid added 19. Shake Milton chipped in with 16 points while Georges Niang added a useful 14 from the bench.
The Utah Jazz meanwhile cemented their place at the top of the Western Conference on Thursday, defeating Atlanta 116-98 on the road.
Jordan Clarkson made 30 points off the bench while Bojan Bogdanovic had 23 with Joe Ingles adding 19. Frenchman Rudy Gobert had 13 points with 15 rebounds.
Just one point separated the teams heading into the final quarter, with Utah clinging to a 75-74 lead.
But the Jazz turned on the offensive power in the fourth quarter, outscoring Atlanta 41-24 to romp home for the win.