SAN FRANCISCO -- The 49ers did not exactly take quick measures to erasethe memory of their lackluster performance Sunday against the New York Giants.The 49ers slogged along offensively Thursday night against the Seattle Seahawksat Candlestick Park.Defensively, they had their difficulties keeping powerful running back MarshawnLynch in check.But the 49ers got their act together just long enough to pull out a less-thanthrilling 13-6 victory over the Seahawks in the 49ers' first game of the seasonagainst an NFC West opponent.Both teams entered the night in a three-way tie for the NFC West lead with 4-2records. The Arizona Cardinals, the next team on the 49ers' schedule, are also4-2.The 49ers returned to the reliable running of Frank Gore to do most of theheavy lifting. The 49ers got away from Gore in a 26-3 beatdown at the hands ofthe Giants on Sunday. Gore carried just eight times for 36 yards.On Thursday, Gore carried 16 times for 131 yards.The 49ers' offense had not scored a touchdown in six quarters when they tookover for their first drive of the second half.Quarterback Alex Smith, who struggled with his accuracy in the first half,completed all six of his attempts during a 10-play, 86-yard drive.He hit one underneath pass after another. The drive was capped with his 12-yardtouchdown pass to Delanie Walker, who received a nice block from Vernon Davisnear the left front of the end zone to enable Walker to get into the end zonefor the first touchdown of the game.The touchdown gave the 49ers took a 10-6 lead with 4:29 remaining in the thirdquarter.Smith finished his night completing 14 of 23 passes for 140 yards with onetouchdown and one interception.BLOWN OPPORTUNITY: The 49ers should've been able to extendtheir lead at the end of the third quarter. Gore's 37-yard run placed the ballat the Seahawks' 8-yard line.After Colin Kaepernick, on his first snap of the game, was stopped for a 1-yardloss, Smith had Randy Moss running along the back line of the end zone. Smithdid not see him until it was too late.By the time Smith threw in Moss' direction, Seattle cornerback Brandon Brownerpeeled off his man to intercept Smith's pass.AFTER A LOSS: The 49ers' continued their streak of keepingteams out of the end zone after a loss. In the games after Jim Harbaugh's fiveregular-season losses, the 49ers entered the game outscoring the opposition bya combined 93-11, which included three field goals and one safety.MISSING MARIO: The 49ers played without Mario Manningham,who started four games this season. He sustained a right shoulder injury atsome point in the 49ers' loss Sunday to the New York Giants.Manningham appeared to be in discomfort with limited range of motion when heworked out on the field approximately two hours prior to kickoff. WithManningham sidelined, Randy Moss and Kyle Williams split most of the time,alongside Michael Crabtree, in two-receiver sets.THIS 'N' THAT: Left tackle Joe Staley received medicalclearance to return to action after sustaining a concussion Sunday against theNew York Giants. He started and played every snap. . .With four receptions last week, running back Frank Gore moved past former 49ersfullback (and current running backs coach) Tom Rathman for second-mostreceptions by a back in 49ers history. Gore needed 35 receiving yards to surpass Rathman and move into third place behind Craig andHugh McElhenny in receiving yards. . .Kicker David Akers, who had missed five of his previous 10 field-goal attempts,got back on track with a 38-yard field goal in the first quarter. He gave the49ers a 13-6 lead with 5:24 remaining in the fourth quarter with a 28-yardfield goal . . Veteran running back Brandon Jacobs was active for the first time all season.He did not play.