It was the third straight loss for the Grizzlies after they had won four in a row and all of the setbacks have been by lopsided scores. They lost by 19 to Dallas last Saturday and then fell by 26 to the Los Angeles Clippers on Monday. Memphis will play five of its next six at home.
San Antonio led by only three at halftime, but limited Memphis to 28 points over the final two quarters.
Rudy Gay had 17 points for the Grizzlies.
San Antonio joined Oklahoma City and the Los Angeles Clippers as the only NBA teams with 30 victories. Going into Wednesday's action no team from the Eastern Conference had more than 24 wins.