The game was tied, 31-31, at the end of regulation.
Washington had a 21-14 halftime lead, but St. Louis quarterback Marc Bulger threw four touchdown passes, two came in the fourth quarter to send the contest into overtime.
Bulger completed 25 of 38 passes for 388 yards; Jackson gained 150 yards on 33 carries and caught a 64-yard touchdown pass; Isaac Bruce scored once on nine catches for 148 yards; and former Redskin Stephen Davis ran for a touchdown for the Rams (7-8), who kept their faint playoff hopes alive.
Betts tied a team record with his fifth straight 100-yard game.
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