With 21 seconds left in the fourth quarter Sunday afternoon at FedEx Field, another game — and possibly the Washington Redskins’ season — appeared to hang heavily over the precipice.

Washington’s double-digit fourth-quarter lead no longer was in play. The San Diego Chargers, who trailed by three, had a first and goal at the Washington 1-yard line with two timeouts, more than enough time left for the given situation.

But a remarkable goal-line stand by the defense forced a game-tying field goal rather than a game-winning touchdown. The coin flip played in Washington’s favor to kick off overtime. And Robert Griffin III and the offense marched 78 yards and scored on a four-yard run by fullback Darrel Young — his third touchdown of the game — to secure a 30-24 victory.

Talk about a sudden change of fortune.

With the win, the Redskins improved to 3-5 on the season and kept hope alive by staying within 11 / 2 games of the Dallas Cowboys for the lead in the downtrodden NFC East at the midway point of the season. Washington has a short turnaround before traveling to Minnesota for a game against the 1-7 Vikings on Thursday, then will face the division rival Philadelphia Eagles. With the win over San Diego, the players had a sense of optimism that they still can turn their season around.

The Post's Mike Jones says the Redskins' win Sunday over the Chargers signals that there is still hope left for their season. (Sarah Parnass/The Washington Post)

“The way we won the game, I think it can be a turning point for us. It’s definitely a bonding experience,” Griffin said, visibly relieved after enduring a week filled with criticism and then a roller coaster of a game. “At the end of the game, when we couldn’t quite execute that four-minute offense all the way to win the game, [the defense] stepped up big for us. . . . Any time you had first and goal from the 1, a lot of people would say the game is over. I think once our defense got that stop and it was overtime and we received it, we knew we were going to win that game.”

The Redskins came dangerously close to losing with 29 seconds left, when Chargers quarterback Philip Rivers completed a six-yard pass to running back Danny Woodhead. Cornerback David Amerson made the tackle as Woodhead dived toward the end zone. Officials initially ruled the play a touchdown, but the call was reversed, and San Diego instead received the ball at the 1. The defenders stuffed Woodhead for no gain on a first-down run with 21 seconds left, then consecutive Rivers incompletions brought on the field goal unit. Nick Novak made a 19-yard field goal with seven seconds left to tie the game at 24.

Washington won the overtime coin toss and got the ball at the 22 following a Joshua Morgan return, and as the offense took the field, the players say they firmly expected to score a touchdown to seal the game.

“We were like, ‘We’re going to score. We’re putting this game away right now.’ That was our confidence,” said running back Alfred Morris, who rushed for 121 yards and a touchdown on 25 carries. “We knew it was going to happen. We were all on the same page, and it took all 11 of us. We know what kind of offense we are. We haven’t shown it, but we know.”

A 19-yard Morris run set the tone for the game-winning drive. Then Griffin completed a 12-yard throw to tight end Jordan Reed on third and eight from the San Diego 45 to keep the series alive. A 17-yard pass from Griffin to wide receiver Pierre Garcon over the middle put the ball at the 26, and a personal foul on the Chargers on the same play moved the ball to the 13. Three plays later, Young took the handoff and ran behind right guard Chris Chester and slipped through the line for a four-yard touchdown run.

“I appreciate the offense as much as I love blocking for them that I’d do anything to get them in the end zone,” said Young, who entered Sunday’s game with four career touchdowns in three-plus NFL seasons.

“It was game-planned for a little bit. Coach [Mike Shanahan] said when we get down there, it was going to be the first run call this week, so I appreciate him trusting me in a situation like that.”

Washington shook off a first half in which it had two field goal attempts blocked and a pass by Griffin in his own end zone deflected and picked off by a Chargers defensive lineman for a touchdown. The Redskins trailed 14-7 at halftime — the lone first-half score coming on a five-yard Morris run — but didn’t take long to tie the score in the third quarter.

Washington marched 74 yards in nine plays and scored on a one-yard run by Young. Then to cap an 11-play, 79-yard drive that began with 7 minutes 2 seconds left in the third quarter and stretched into the opening minutes of the fourth quarter, the Redskins went to Young again — also on a one-yard run up the middle.

“Young does a heckuva job for us on special teams, as a fullback, and he can actually go in there and work as a tight end,” Shanahan said. “We run so many running plays with a halfback, and he’s a blocker — they lose him. And so to put him in that situation says a lot about our running game and our offensive line, and D.Y. does have the skills to make people miss. . . . When you give it to the fullback down there and he finds a way to get in there three different times, but it didn’t surprise me.”

All three of Young’s carries came on third downs. The Redskins converted 12 of 17 third-down attempts in all after struggling mightily in that area much of the season. The offense had one of its most balanced performances of the season with 209 rushing yards on 40 carries and 291 passing yards as Griffin completed 23 of 32 attempts.

Two turnovers forced by the defense — a first-half interception by cornerback E.J. Biggers and a fourth-quarter pick by Amerson — aided the offensive effort. Amerson’s play set up a 47-yard field goal for a 24-14 lead.

But late-game heroics were still required.

Rivers completed a 16-yard touchdown pass to wide receiver Keenan Allen to cut the lead to 24-21 with 2:49 left, and San Diego got the ball back and marched 91 yards in 14 plays before settling for the field goal.

“It was time that the defense had to step up,” said linebacker London Fletcher, who led the team with 13 tackles. “It was a great team win. Goal-line stand, big statement there, making them kick a field goal, the offense stepping up. That was a big stand and a big drive there. It can be some momentum for us. Hopefully we can carry this over Thursday night.”