Washington Redskins survive the loss of rookie QB Robert Griffin III and pull off a last-second comeback, keeping playoff hopes alive with flair. (The Washington Post)

His first inclination, the one forged by instinct and an intense will to compete, was to keep playing, at all costs. So when the first Washington Redskins teammate got to Robert Griffin III’s side as he lay sprawled on the FedEx Field turf late in Sunday’s fourth quarter after a crushing hit by a 340-pound nose tackle, Griffin barked out his orders.

“He’s like, ‘Just get me up, get me to the huddle — quick, we gotta hurry,’ ” tight end Logan Paulsen said. “So I got him up, and then I realized, man, he could barely walk.”

The events of the several minutes that followed will go down in Redskins lore. Griffin, in severe pain from an injury revealed after an MRI exam to be a sprained knee, was coaxed to the sideline for one play, with the Redskins still trailing, 28-20, but demanded to go right back in. He lasted four more plays, hobbling around enough to complete two passes and drive the Redskins into the Baltimore Ravens’ red zone, less than 20 yards from a potential touchdown.

Finally, after an incompletion that resulted in a penalty for intentional grounding, Griffin crumpled to the ground, unable to take another step, let alone make another play. As the Redskins finished the improbable last-second comeback, Griffin could only watch and hope. Backup quarterback Kirk Cousins threw a touchdown pass with 29 seconds remaining and capped the drive with a successful two-point conversion. Kicker Kai Forbath drilled a 34-yard field goal in overtime to complete a 31-28 victory.

“You have to do what’s right for the team,” Griffin said later. “If I played the rest of that game, I probably would’ve hurt myself even more. So you have to trust those guys, and trust yourself when you know enough is enough.”

Griffin’s father, Robert Griffin Jr., answered a reporter’s question about the extent of his son’s knee injury in a text message: “Knee better than yours and mine.”

The Redskins remained one game behind the first-place New York Giants in the NFC East after the Giants walloped the New Orleans Saints on Sunday, and one game back of the Seattle Seahawks and Chicago Bears in the race for one of two wild-card playoff spots in the NFC.

The Redskins will play their next two games on the road in Cleveland and Philadelphia against last-place teams with losing records, before closing the season at home Dec. 30 against the Dallas Cowboys.

Griffin’s immediate future, and the Redskins’ playoff hopes, now may depend largely upon how quickly the star rookie can heal. Having suffered a torn anterior cruciate ligament in college — which cost him most of his sophomore season at Baylor — Griffin knows what the worst-case injury feels like. A return from a sprained knee is more difficult to predict.

Griffin was actually lying on a training table behind the Redskins’ bench, flat on his back — a doctor flexing his knee in all directions, jabbing it, twisting it — as Cousins completed the game-tying touchdown drive in regulation. A teammate shrouded him with a giant, burgundy coat so the cameras couldn’t intrude upon his pain.

There were 36 seconds left in the game and Griffin couldn’t see what was taking place on the field, but he had his quarterback’s headset over his ears, and he heard the play call go over the radio to Cousins for the two-point conversion attempt that would tie the game. It was a quarterback draw — Griffin’s signature red-zone play.

Griffin smiled, he said later, and when the roar of the crowd told him the play had succeeded, he pumped his fist gently.

“I channeled my inner RGIII,” Cousins joked with Griffin later.

But beginning with the overtime kickoff, Griffin seemed to become acutely aware of all the eyes fixed upon him, looking to the Redskins’ superstar rookie for a sign, good or bad. He gave Redskins Coach Mike Shanahan a hug, appearing intensely emotional, on the verge of tears. He limped around the Redskins’ sideline, wearing a bulky brace on his injured knee, firing up his teammates.

“He just said, ‘Let’s finish this off,’ ” running back Alfred Morris said. “That’s just the type of person Robert is. I’m not surprised by his actions, wanting to get back in the game, or shedding a tear or two because he wasn’t able to be out there helping his team win.”

In his postgame news conference, as if cognizant of how his mood would be interpreted by the fans, Griffin flashed his toothy smile and cracked a couple of jokes. “As soon as I got hit . . . I screamed — like a man, of course,” he said, to a roomful of laughter.

In a quieter moment in the Redskins’ locker room, he hugged his teammates, aware of what awaited him — an MRI tube, an anxious few hours, a diagnosis that would determine whether he plays again this season.

“He said, ‘I love you, man,’ ” fullback Darrel Young said. “I just said, ‘I love you, too.’ ”