Jason Myers kicked a 42-yard field goal as time expired in overtime Monday night, allowing the visiting Seattle Seahawks to hand the San Francisco 49ers their first defeat of the season, 27-24.
After rookie 49ers kicker Chase McLaughlin missed a potential game-winning 47-yarder in the extra session, Russell Wilson set up Myers' heroics with an 18-yard run into San Francisco territory.
The win allowed the Seahawks (8-2), unbeaten on the road this season at 5-0, to move within a half-game of the first-place 49ers (8-1) in the NFC West.
San Francisco had been the NFL's last remaining unbeaten team.
In a mistake-filled game that featured defensive touchdowns by linemen Jadaveon Clowney of the Seahawks and DeForest Buckner of the 49ers, San Francisco's McLaughlin, signed earlier in the week off the scrap heap to replace injured Robbie Gould, forced the overtime when he made his third field goal, a 47-yarder with one second left in regulation.
The score matched a 46-yarder by Myers to 1:45 to go.
The 49ers trailed 21-10 early in the fourth quarter before Buckner's 12-yard fumble return, a two-point conversion pass from Jimmy Garoppolo to Kendrick Bourne and a 39-yard field goal by McLaughlin produced a tie with 6:21 to play.
Buckner's momentum-swinging play capped a wild sequence in which Wilson, in the process of being sacked by Arik Armstead and K'Waun Williams, bobbled the ball into the hands of his teammate, guard Germain Ifedi.
The offensive lineman attempted to advance the ball but was stripped by Fred Warner and fumbled, with Buckner picking it up and racing 12 yards for a touchdown with 12:12 remaining.
The 49ers then forced a punt on Seattle's next possession, after which the NFC West leaders drove 48 yards in eight plays to set up McLaughlin's second field goal.
Clowney's touchdown came in a more conventional manner. He scooped up a rolling football after a sack by Jarran Reed had forced a Garoppolo fumble and took it 10 yards for Seattle's first score with 2:51 remaining in the half.
The 49ers built a 10-0 lead in the first quarter on a 43-yard field goal by McLaughlin and a 10-yard touchdown pass from Garoppolo to Bourne.
Down 10-7 at the half, the Seattle grabbed a 21-10 lead in the third quarter on a 3-yard pass from Wilson to tight end Jacob Hollister and a 1-yard plunge by Chris Carson.
Wilson finished 24 of 34 for 232 yards with one touchdown and one interception. He also rushed for 53 yards on six carries.
Carson was the game's leading rusher with 89 yards on 25 attempts.
Garoppolo went 24 of 46 for 248 yards, also with one TD and one interception.
San Francisco's Deebo Samuels had eight catches for a game-high 112 yards.
--Field Level Media