Geno Smith scored on a 13-yard scramble with 12 seconds remaining as the Seattle Seahawks upended the host San Francisco 49ers 20-17 Sunday afternoon in Santa Clara, Calif.

The Seahawks (5-5), who were coming off their bye week, snapped a two-game skid and won for just the second time in their past seven games. Their victory created a three-way tie for second place in the NFC West, with Seattle, San Francisco (5-5) and the Los Angeles Rams (5-5) all one game behind idle Arizona (6-4).

Smith was 25-of-32 passing for 221 yards and one interception. Jaxon Smith-Njigba made 10 catches for 110 yards and DK Metcalf, who missed the previous two games with a knee injury, added seven receptions for 70 yards.

Brock Purdy was 21-of-28 passing for 159 yards, throwing for one touchdown and rushing for another for the 49ers, who had a two-game winning streak snapped.

Christian McCaffrey, playing in his second game of the season after recovering from Achilles tendinitis, finished with 106 total yards (79 rushing, 27 receiving). Jauan Jennings posted 10 receptions for 91 yards and a score.

The Seahawks got the ball on their own 20-yard line with 2:38 remaining after a punt. Smith was 7-of-8 passing for 54 yards on the deciding drive and had a 16-yard scamper along with his 13-yard scoring run.

Trailing 13-10, Purdy threw a 3-yard touchdown pass to Jennings with 9:33 remaining, capping a 14-play, 70-yard drive that lasted nearly nine minutes.

The Seahawks went for it on fourth-and-inches from the San Francisco 37-yard line with 3:56 remaining. They lined up Zach Charbonnet as a fullback and handed him the ball, a play that worked in the first half, but he was stopped for no gain.

However, the 49ers were unable to run out the clock, giving the Seahawks one last chance.

San Francisco defensive end Nick Bosa appeared to aggravate a hip injury while sacking Smith in the third quarter and didn’t return.

On the same drive on which Bosa was hurt, the Seahawks drove for their first touchdown. Kenneth Walker III, who had 54 yards on 14 carries, gave Seattle a 13-10 lead with his 1-yard run.

The 49ers led 7-6 at the half on a 10-yard scoring run by Purdy. He scrambled to his right and dove with the ball outstretched just inside the pylon.

Seattle’s Jason Myers kicked 52- and 57-yard field goals in the first half. The 49ers’ Jake Moody booted a 33-yarder early in the third to extend the hosts’ lead to 10-6.

San Francisco All-Pro tight end George Kittle was inactive because of a hamstring injury.