GLENDALE, Ariz. — On an almost-perfect Monday night for Alex Smith, the San Francisco 49ers flexed their NFC West dominance with a 24-3 flattening of the Arizona Cardinals.

Smith completed 18 of 19 passes for 232 yards and three touchdowns — two to Michael Crabtree and one to Randy Moss — to help San Francisco (6-2) open a two-game lead in the division and send Arizona (4-4) to its fourth straight loss.