Josh Giddey's Oklahoma City have pushed NBA title contenders Boston to the brink, falling just short of a second huge road win in as many days.
Giddey (16 points, seven rebounds, four assists) backed up his triple-double against the New York Knicks barely 24 hours earlier as the Thunder led by as many as 15 in the third quarter.
Boston's Marcus Smart scored 20 of his 22 points in the second half, though, as the new league leaders prevailed 126-122 for a seventh-straight win.
But a 37-26 final quarter hurt the Thunder, Giddey missing a triple - he was one-of-six for the night - with the scores tied and 90 seconds to play.
Smart made one at the other end and Derrick White nailed another to give the hosts the decisive buffer.
The Australian also left Boston with a forgettable place on the highlight reel, throwing his in-bound pass into the backboard and turning it over when he attempted to catch the ball and pass it again.
The loss leaves the Thunder, the NBA's youngest team on average, mid-table in the west with a 6-8 record.
Milwaukee's 121-106 loss to Atlanta dropped them to 10-3 this season and allowed Boston (11-3) to assume sole ownership of the eastern conference and the NBA's best record.
Bam Adebayo scored 30 points, including a pair of free throws to put Miami up for good with 35 seconds left as the Heat rallied back from a 13-point fourth-quarter deficit.
Chasing a game-winner, Cameron Payne missed a lay-up, a jumper from Booker was sensationally blocked by Butler and then a three-pointer from Booker fell short.
Elsewhere, Jordan Poole had 36 points in Golden States' defeat of San Antonio, the Toronto snuck past Detroit, Charlotte beat Orlando and the Los Angeles Clippers got the better of the Houston Rockets.