Diaw netted 16 points, Tiago Splitter added 15 with 12 rebounds and Tony Parker also put in 15 points as the Spurs recorded a fourth straight victory.
The Wizards, meanwhile, dropped to 0-12, extending the worst start in franchise history.
Jordan Crawford and Kevin Seraphin combined for 37 points in the setback.
Costly malfunction causes beer flood at Boston-area brewery
Megyn Kelly: Santa Claus and Jesus are both white men