SAN FRANCISCO (AP) -- Alex Smith threw a 12-yard touchdown pass to Delanie Walker late in the third quarter and San Francisco held off the Seattle Seahawks 13-6 on Thursday night as the 49ers won their long-awaited division opener.

Frank Gore ran for 116 yards and the 49ers (5-2) took over sole possession of first place in the NFC West by making just enough plays to win this defense-first game, featuring two teams allowing fewer than 16 points per game.

Walker's score was San Francisco's first touchdown in seven quarters after an embarrassing 26-3 loss to the New York Giants on Sunday in a lopsided rematch of the NFC championship game.

Smith went 14 of 23 for 140 yards in another subpar performance.

NFC rushing leader Marshawn Lynch finished with 103 yards for Seattle (4-3).