The Spurs have a 3-0 advantage in the Western Conference quarterfinal series and can move deeper into the playoffs with another road victory over Los Angeles Sunday.
The Los Angeles post-season hopes were all but doomed when Kobe Bryant was lost until next season, and San Antonio made sure the Lakers stayed down by jumping to a 12-point lead after one quarter.
Duncan scored six straight points to give San Antonio the lead for good just 5 minutes into the contest and he finished with 26 points and nine rebounds. Duncan made 12-of-16 from the field.
Tony Parker added 20 points for San Antonio and the Spurs' bench combined for 46 as the game turned into a rout. Los Angeles put up little resistance in the second half and the Spurs piled it on by hitting 61 percent from the field.
Dwight Howard scored 25 points for the Lakers, Darius Morris had 24 and Andrew Goudelock added 20. The remainder of the Lakers scored only 20 points.