Receiver Eric Saubert made the game-winning two-point play for Seattle.
Seattle engineered a stunning comeback to defeat the Los Angeles Rams in overtime, clinching their spot in the NFL play-offs.
Overcoming a sixteen-point deficit in the fourth quarter, the Seattle squad emerged victorious by a single point at home, registering their fifth straight victory.
While the Rams had become the first to earn a playoff berth earlier on Sunday, the Seattle team booked their return to the postseason after a two-year absence.
With this outcome, the Seattle now lead their Conference race with a twelve and three record, replacing the Los Angeles, who fell to the number five seed with an 11-4 record.
Signal-caller Darnold threw two picks but recovered to make two scoring throws, including the second TD to star receiver Jaxon Smith-Njigba in overtime.
The visitors held a six-point advantage at the break before Kenneth Walker III broke free for a 55-yard scoring dash for the home side.
Rams cornerback Wallace then returned Darnold's initial pick for a big return, setting up a short touchdown by Blake Corum on the next play.
In the final stanza, a scoring pass from Matthew Stafford to Nacua extended the Rams' lead to sixteen points, but Shaheed provided Seattle's hope with a spectacular punt return.
Darnold then connected with Barner in the end zone, and a successful conversion forced the contest into an extra period.
Although Puka Nacua scored for his another TD in overtime, Jaxon Smith-Njigba answered in kind to set up the game-winning conversion.