Walker's floater from the lane with 7.8 seconds left in regulation forced an overtime and his reverse layup in extra time put the Bobcats on track for only their fourth road win of the season.
Tayshaun Prince fired in 21 points and grabbed seven boards for Detroit, but it wasn't enough to prevent the end of the Pistons' four-game winning streak.
Greg Monroe provided 18 points and 14 rebounds for Detroit.
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