Seattle (12-4) had a slow start and appeared in serious trouble when Jeff Wilson Jr. ran for a 7-yard touchdown early in the fourth quarter to push the 49ers ahead 16-6.
But the Seahawks responded with their first touchdown when Russell Wilson avoided pressure and hit Lockett for a diving 6-yard touchdown in the back of the end zone. Jason Myers missed the extra point and the Seahawks trailed 16-12.
Seattle forced the 49ers to punt on the ensuing possession and then methodically marched 85 yards on 14 plays and scored the go-ahead touchdown on fourth down on Wilson's 4-yard throw to Lockett.