OKC allowed a 20-10 run to start the fourth quarter after entering the final stretch trailing by just one. The Grizzlies took advantage of size and fresh legs as they pulled away thanks in part to strong play inside from center Jonas Valaciunas.
Although the Thunder held Memphis at bay on the glass, the team still gave up 52 points in the paint and scored just 22 down low themselves. They also finished with 17 turnovers.
Valanciunas was one of three Grizzlies to score at least 20, capping a double-double with 22 points (9-for-12) and 11 rebounds. Brandon Clarke was a frontcourt pest as well, scoring 12 points (5-for-7) with six boards.
Shai Gilgeous-Alexander returned for the Thunder after missing four straight games.
SGA scored a game-high 22 points (6-for-14) with six assists and three rebounds. Center Mike Muscala scored 21 off the bench, going 5-for-9 from the three-point range.
Oklahoma City struggled with efficiency early in the game, turning the ball over 13 times in the first half. The Thunder still only trailed 57-56 at the break and after tidying up offensively, were down just 86-85 after the third quarter.
Memphis pulled away down the stretch as Grayson Allen scored 11 of his 22 points in the fourth quarter while Valanciunas poured in nine. The Thunder allowed 36 points as they closed out the second end of a back-to-back with their fifth loss in six games.
Six players total scored in double digits for Oklahoma City. Darius Bazley scored 18 points with seven rebounds, Theo Maledon scored 14, Luguentz Dort scored 11, and Isaiah Roby chipped in 10.
The Thunder continue their road trip Friday at Milwaukee. Tipoff is scheduled for 7 p.m. CT.