The Clippers trailed by 25 in the second quarter and were down 83-60 in the third before storming back to tie the game at 89 in the fourth. It was 91-all before Williams scored every Los Angeles point during a decisive run that put the Clippers up 107-96.
Williams finished with 39 points. Detroit's Blake Griffin had 24 points and 11 rebounds against his former team, and Reggie Jackson added 29 points for the Pistons.
The Pistons led 40-22 after a first quarter in which they made eight 3-pointers. Los Angeles took three timeouts in the game's first 5:25, but that didn't do much to stem the tide.
Detroit led 65-47 at halftime. It was still a comfortable margin until the very end of the third, when the Clippers -- who were starting a six-game road trip -- began to make a game of it.
Williams made a pair of 3-pointers during his 16-point run in the fourth. Detroit scored only 14 points in the final period.
Clippers: Montrezl Harrell scored 16 points and Mike Scott added 15. Only one starter was in double figures, and that was Shai Gilgeous-Alexander, who scored 14.
Pistons: Detroit finished 17 of 42 from 3-point range, going 6 of 22 in the second half.
The Clippers' reserves came in averaging a league-best 51.3 points per game, and they outscored Detroit's bench 80-17. The Pistons' starters outscored their Los Angeles counterparts 84-31, but it wasn't enough.
Clippers: Visit Toronto on Sunday.
Pistons: Host Denver on Monday night.
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Griffin puts up a double-double vs. Clippers
Blake Griffin records 24 points and 11 rebounds against his former team.