The Chargers were down 24-21 with less than 1 minute remaining in regulation when Danny Woodhead appeared to have scored on a touchdown dive. The ruling on the field, however, was overturned on a video review and Washington followed with a goal line stand, forcing the Chargers to settle for a score-tying 19-yard field goal from Nick Novak as time ran out.
On the first possession in overtime, Alfred Morris gave the Redskins (5-3) good field position with a 19-yard run.
Robert Griffin III hit tight end Jordan Reed for a 12-yard gain on a third-and-8 situation, and two plays later connected with Pierre Garcon on a 17-yard completion.
A personal foul call at the end of the play moved the ball to the San Diego 13-yard line.
Morris (25 carries, 125 yards, one TD) followed with two runs, putting Washington on the 4-yard line, and then, on third-and-1, Young bulled into the end zone for the game-winner as the Redskins notched a second victory in three games.
Griffin was 23-of-32 passing for 291 yards and an interception, and Garcon caught seven passes for 172 yards.
Chargers quarterback Philip Rivers was 29-of-46 passing for 341 yards and two touchdowns with two interceptions. Keenan Allen caught eight passes for 128 yards and a touchdown for the Chargers, who fell to 4-4.