SAN FRANCISCO – Wobbly, mistake-prone and heading toward their second loss at home in four days, the 49ers got their groove back Thursday by returning to their ground-and-pound roots.

Trailing the visiting Seahawks 6-3 in the third quarter, the 49ers started feeding the ball to Frank Gore, and he and his blockers responded with a 10-play touchdown drive into the heart of Seattle's defense that propelled San Francisco to a 13-6 win.

"That was the most physical 30 minutes of football in the second half I've ever seen them play," said Jim Harbaugh, who threw compliments all around but had the most for an offensive line that helped create 175 rushing yards and a defensive line that sealed the game in the fourth quarter.

Gore ran three times for 17 yards on the third-quarter drive and caught two short passes for 27 yards to get the 49ers, who had punted on the previous three possessions, to Seattle's 23-yard line.

From there, quarterback Alex Smith emerged from a first-half fog, hitting Michael Crabtree on third down and finding forgotten target Delanie Walker for a 12-yard touchdown on the next play. Walker caught the ball in stride and received a nice block from fellow tight end Vernon Davis to reach the corner of the end zone.

Walker had been the hero of the team's come-from-behind win in Detroit a year earlier, catching a six-yard touchdown pass with 1:51 remaining. But he had become an invisible man in the team's passing offense since then, and Thursday's touchdown was his first since the game in Detroit.

"They feel like I'm not getting the ball, and they leave me open," Walker said of opposing defenses. "Alex saw that. I was wide open, and Alex saw that."

That score masked a first half full of errors, bad tackles and bad judgment from the 49ers, who still seemed to be reeling from an ugly loss to the New York Giants four days earlier.

Cornerback Perrish Cox lost track of Seattle wide receiver Ben Obomanu, who caught a short pass for a 36-yard gain. Aldon Smith missed a tackle on a 15-yard run by former Cal star Marshawn Lynch, who finished with 103 yards, while cornerback Tarell Brown lost sight of the ball on a 27-yard catch-and-run by Sidney Rice.

Walker's touchdown seemed to awaken the defense, too.

On the ensuing Seattle possession, rookie quarterback Russell Wilson threw an arcing pass downfield for ex-49er Braylon Edwards, and safety Dashon Goldson swooped in like an outfielder for the interception.

Seattle's offense didn't get beyond the San Francisco 17-yard line, and Wilson completed only 9 of 23 passes for 122 yards.

"We didn't want to call it a must-win," said safety Donte Whitner, "but we felt like it was a really big game and we really wanted to win it, and we came out and did what we were supposed to do."

Lynch was the second straight rusher to surpass 100 yards against the 49ers. But he was outdone by Gore, who finished with 131 yards on the ground and another 51 yards on short pass plays.

Seattle entered the game with the fourth-rated defense in the league, and the Seahawks had made a big statement Sunday by defeating the defending AFC champion New England Patriots. The 49ers, however, attacked Seattle's strength – its defensive midsection – as Gore broke off runs of 37, 20 and 18 yards.

Gore played most of the game after being hit in the back in the second quarter. He was not on the field as the 49ers tried to run out the clock at game's end, but he said he'd be fine.

The 49ers don't play again for 10 days – on "Monday Night Football" against another division opponent, the Arizona Cardinals.

"I'll be all right. Coach wants me to be smart," Gore said about leaving the game at the end. "We've got a long season, a tough road down the stretch."

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