Memphis won its fourth in a row and climbed within 1 1/2 games of San Antonio for the lead in the Southwest Division.
The teams combined to score just nine points in the extra period after San Antonio's Tony Parker had forced the overtime by hitting a 3-pointer in the final second of regulation.
The Spurs missed nine of their 10 field goal attempts in the overtime, including a 3-point try by Manu Ginobili with 2 seconds left that would have brought about a second extra session.
San Antonio lost for just the third time in 12 games.
Parker led all scorers with 31 points, Ginobili had 14 and both Tim Duncan and Tiago Splitter had 13. Duncan also grabbed 15 rebounds.