Receiver Saubert made the decisive two-point conversion for Seattle.
The Seattle Seahawks staged a stunning comeback to defeat the Rams in extra time, clinching their place in the NFL play-offs.
Rallying from a 30-14 hole in the final period, the Seattle squad triumphed by a single point at home, notching their fifth consecutive win.
While the Los Angeles had already secured a playoff spot earlier on game day, the Seahawks secured their place to the postseason after a two-year hiatus.
With this outcome, the Seattle have taken over their division's standings with a 12-3 mark, replacing the Los Angeles, who fell to the number five seed with an 11-4 record.
Signal-caller Sam Darnold threw two interceptions but recovered to deliver two touchdown passes, including the tying TD to wideout Smith-Njigba in the extra period.
The visitors held a six-point advantage at half-time before Walker broke free for a 55-yard scoring dash for Seattle.
Los Angeles cornerback Josh Wallace then took back Darnold's initial pick for 56 yards, setting up a one-yard touchdown by Blake Corum on the next play.
In the final stanza, a scoring pass from Matthew Stafford to Nacua pushed the Rams' lead to sixteen points, but Rashid Shaheed provided Seattle's comeback with a spectacular punt return.
Darnold then connected with AJ Barner in the end zone, and a converted two-point play forced the contest into an extra period.
Although Puka Nacua scored for his another TD in OT, Jaxon Smith-Njigba answered in kind to setup the game-winning score.