Marc Gasol chipped in 17 points and nine boards for the Grizzlies, who exacted a bit of revenge on the Spurs. San Antonio snapped Memphis' franchise-record 22-game home winning streak on Dec. 5. The teams then played a triple-overtime thriller won by the Grizzlies, 117-116, on Dec. 17.
Tayshaun Prince totaled 12 points for the Grizzlies, who have won back-to-back contests following a four-game skid.
The Spurs, who played without Kawhi Leonard (bruised right hand) and Tony Parker (strained left hamstring), lost for the seventh time in nine games.
The Grizzlies, off to their best start in franchise history at 23-8, trailed by only a point, twice. Both of those times came in the early stages of the game.
Memphis shot 13-of-21 in the first quarter, led by a 7-of-8, 16-point effort from Conley. The hosts embarked on an 11-1 burst, capped off by a layup from Tony Allen and a technical free throw from Courtney Lee for a 13-4 lead.
Conley's 3-pointer in the waning seconds provided a 30-20 cushion after 12 minutes.
The Spurs struggled to a 6-of-19 shooting performance in the second quarter, and trailed 52-38 at the break. The visitors were behind 74-63 going to the fourth.
Duncan's jumper had the Spurs within 80-77 midway through the fourth, but Gasol countered with a jumper and Prince nailed a long-range 2-pointer for an 84-77 edge. Conley then made two from the charity stripe with 3:37 left to cap the 6-0 run and essentially seal the outcome.