SAN FRANCISCO - Pete Carroll pulled up a chair and sat next to Russell Wilson in one corner of Candlestick Park's visiting locker room, listening to his rookie quarterback and asking questions.

Both are still searching for some answers.

Wilson threw for 122 yards and an interception, his receivers dropped several passes and the Seattle Seahawks lost 13-6 to the San Francisco 49ers on Thursday night to fall out of a first-place tie in the NFC West.

Seattle (4-3) has lost all three division games, and all three came on the road.

"The way we lost was frustrating," said Wilson, who completed 9 of 23 passes. "We could have done some things better. I could have done some things better."

Now Seattle - and everyone else - is back to chasing San Francisco atop the division.

Smith threw a 12-yard touchdown pass to tight end Delanie Walker late in the third quarter for a 10-6 lead. San Francisco (5-2) relied on its dominant defense to harass Wilson and hold off Seattle's final rally.

"We found ourselves in a real slugfest here today," Carroll said. "I'm not surprised it could have gone that way with two good defenses and two teams committed to running the ball. And there was plays in this game that I'll always want to know, what would have happened if we made this play or made that play? It was so close."

Frank Gore ran for 131 yards and the 49ers made just enough plays to win a defense-dominated game that featured two teams allowing fewer than 16 points per game.