The Thunder staged a furious rally at the end of regulation to force overtime, but had nothing left in the extra session as Toronto scored the first nine points, including five by forward Kawhi Leonard, to win 123-114 in Oklahoma City on Wednesday night.
The loss made the bottom half of the Western Conference playoff race even tighter. The Thunder fell into a tie with the Spurs and Clippers, who all have identical 42-30 records, for the sixth seed.
The Jazz, which won in New York, moved into fifth at 42-39.
For a moment it looked as if Oklahoma City was going to stage a momentous comeback.
The Raptors led by eight with just over one minute remaining in regulation but two Paul George three-pointers and a Russell Westbrook layup tied things up with 4.8 seconds remaining.
But the overtime session belonged to Toronto (51-21), who remain two games behind Milwaukee for first place in the East.
Pascal Siakam had 33 points and 13 rebounds for Toronto while Leonard added 22. Westbrook finished with 42 points, 11 rebounds and six assists.
Philadelphia 118, Boston 115: Joel Embiid had 37 points, 22 rebounds and a key block on Kyrie Irving with 35 seconds remaining, and Jimmy Butler scored 15 of his 22 points in the fourth quarter to lead the 76ers over the Celtics in Philadelphia for their sixth straight victory. The Celtics defeated the 76ers in the playoffs last season and won their first three contests this season. Irving finished with 36.
Memphis 126, Houston 125 (OT): James Harden scored 57 points, his seventh game with 50 or more this season, to go along with eight assist, seven rebounds, two steals and two blocks, but Mike Conley and Jonas Valanciunas matched him shot-for-shot as the Grizzlies topped the Rockets in Memphis. Conley finished with 35 points and eight assists while Valanciunas had 33 and 15 rebounds, and made one of two free throws with 0.1 seconds left to secure the win.
Miami 110, San Antonio 105: Goran Dragic scored 22 points to lead six Heat players in double-figures as it handed the Spurs just their eighth loss in San Antonio this season.
Portland 126, Dallas 118: Damian Lillard scored 33 points on 18 shots and added 12 assists to lead the Trail Blazers past the Mavericks. Luka Doncic had 24, five rebounds and six assists in a losing effort.
Chicago 126, Washington 120 (OT): Kris Dunn scored eight of his season-high 26 points in overtime and added 13 assists to lead the Bulls past the Wizards in Chicago.