Oklahoma, who were 13 points behind in the second quarter, recovered to win after trailing by at least 12 points for the fourth straight game.
The defending champions, who had not scored fewer than than 44 points in a half this season, managed only 27 in the second half at Paycom Center in Oklahoma City.
Victory improved Oklahoma's record to 30-5 and extended their lead at the top of the Western Conference.
The game was the Thunder's second of three in a row against the Eastern Conference's top three teams, having beaten the third-placed New York Knicks on Friday.
On Wednesday they take on Eastern Conference leaders the Cleveland Cavaliers, who beat the Charlotte Hornets 115-105 at home to claim a 10th consecutive win.
Darius Garland scored 25 points and Jarrett Allen and Donovan Mitchell 19 apiece for Cleveland.
Jalen Green scored 33 points and Amen Thompson 23 as the Houston Rockets beat the Los Angeles Lakers 119-115 in Houston.
The Sacramento Kings made it four straight wins with a 129-99 victory over the Golden State Warriors 129-99 in San Francisco.
CJ McCollum scored 25 points as the New Orleans Pelicans won 110-98 at the Washington Wizards, while the Utah Jazz triumphed 105-92 at the Orlando Magic.