Alex Smith started for the 49ers in place of quarterback Troy Smith. He completed 17 of his 27 passes for 255 yards, three touchdowns and no interceptions.
On the other side of the ball, Seattle quarterback Matt Hasselbeck threw four interceptions.
San Francisco has a short week coming up with a Thursday game against the Chargers in San Diego at Qualcomm Stadium. The 49ers will then finish in St. Louis and at home against Arizona.
View gameday stats at NFL.com's Game Center.
You can also discuss the game with fans in the 49erswebzone.com forums.