Receiver Saubert executed the game-winning two-point play for Seattle.
Seattle engineered a remarkable comeback to overcome the Rams in extra time, clinching their spot in the postseason.
Rallying from a 30-14 hole in the final period, the Seattle squad triumphed by a single point at home, notching their fifth consecutive victory.
While the Rams had already secured a playoff spot earlier on game day, the Seahawks secured their place to the play-offs after a two-year hiatus.
With this outcome, the Seattle have taken over their division's standings with a twelve and three mark, replacing the Los Angeles, who dropped to the number five seed with an eleven and four standing.
Signal-caller Darnold threw two picks but regrouped to make two touchdown passes, culminating in the tying TD to star receiver Smith-Njigba in overtime.
The visitors held a six-point advantage at the break before Walker burst through for a long scoring dash for the home side.
Rams cornerback Wallace then took back Darnold's first pick for 56 yards, setting up a short score by Corum on the next play.
In the final stanza, a scoring pass from Matthew Stafford to Nacua pushed the advantage to 30-14, but Rashid Shaheed ignited the comeback with a spectacular return for a score.
Darnold then connected with Barner in the end zone, and a successful conversion sent the game into an extra period.
Although Puka Nacua raced in for his second touchdown in OT, Smith-Njigba responded in kind to set up the game-winning conversion.