After Walker's touchdown, Dashon Goldson intercepted a deep pass by Wilson to thwart Seattle's next drive after NaVorro Bowman clobbered the former Wisconsin quarterback as he was trying to throw.
Smith gave the ball back with an interception of his own early in the fourth quarter. His fifth interception of the season matched his total from all of 2011.
Harbaugh went to backup Colin Kaepernick for one keeper play that lost a yard, Smith returned for third-and-goal on the 7. He scrambled to his left looking for an open receiver and Brandon Browner jumped in front of a pass intended for Randy Moss.
That gave Seattle the ball back with 11:58 remaining. Yet again, the Seahawks couldn't capitalize on a night of missed opportunities and dropped balls.
Wilson, who spoke leading up to the game that he couldn't wait for his introduction to this heated rivalry, was sacked twice and never looked in rhythm. Aldon Smith sacked him with 1:25 left, then Paul McQuistan was called for a chop block on Smith in the end zone with 43 seconds left. It would have been an automatic safety, but the 49ers declined the penalty.
The play was reviewed and Seattle was short of the first down.
Steven Hauschka kicked a 52-yard field goal as Seattle scored first for the seventh time in as many games this year. He added a 35-yarder early in the second quarter but missed wide left on a 51-yard try later in the quarter.
"We've got to figure something out," said wide receiver Golden Tate, who had two drops. "We've got to figure out a way to get it done. It's not over. The season's not over."
NOTES: Seattle lost LB Malcolm Smith to a concussion on the opening kickoff, then WR Doug Baldwin later injured his ankle and did not return. ... 49ers WR Mario Manningham was inactive with a shoulder injury. ... Ted Ginn Jr. had a 38-yard return late in the first half for the 49ers.
Antonio Gonzalez can be reached at: www.twitter.com/agonzalezAP
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