With the Rams needing only a field goal after stuffing the Seahawks on fourth down on the first possession of OT, Matthew Stafford went for the win by throwing a deep ball to Robinson, who was well covered by cornerback Riq Woolen. With his one free hand, Robinson grabbed the ball in the end zone and secured it as he fell to the turf.
Stafford threw for 298 yards and two touchdowns for the Rams (4-4), who have won three straight after losing four of their previous five. Robinson finished with six catches for 94 yards and both scores.
Geno Smith threw for 363 yards with three touchdowns and three interceptions for the Seahawks (4-5), who have lost four straight at home and five of six overall to fall into last place in the bunched-up NFC West. Jaxon Smith-Njigba had seven catches for a career-best 180 yards and two scores.
The Rams rallied from a 13-3 deficit and took a 20-13 lead on Kamren Kinchens' 103-yard interception return early in the fourth quarter, only to let the Seahawks tie it when Smith connected with Smith-Njigba for a 14-yard touchdown with 51 seconds left.
Stafford tried to drive the Rams into position for a winning field goal, but the drive stalled just short of midfield.