The Washington Post’s mike Jones breaks down the Redksins’ win over the Dallas Cowboys last night for the team’s first division title since the 1999 season. (The Washington Post)

They are too young to understand the angst, too new to this region to understand why there were tears being shed in the stands above them at FedEx Field. In the context of the Washington Redskins’ history, Robert Griffin III and Alfred Morris are mere babies. Some Redskins fans have emotional scars that are older.

But on a frigid night that felt unmistakably like playoff weather, jarring long-dormant memories of glorious winters past, the two rookies marched the Redskins through the heart of the Dallas Cowboys’ defense and straight into the NFL playoffs.

There will be January football, playoff football, at FedEx Field next weekend for the first time in 13 years, following the Redskins’ 28-18 victory over the hated Cowboys on Sunday night.

Next Sunday at 4:30 p.m., the Redskins, newly crowned champions of the NFC East division, will host the Seattle Seahawks in a first-round playoff game, the first at FedEx Field since Jan. 8, 2000.

As the final seconds ticked down, fans ignored the cold, and the oncoming blitz of winter behind it, and rejoiced in a season extended by a victory on a night when a loss would have ended it.

As many expected, the rookie phenom in the Redskins’ backfield was clearly the best player on the field Sunday night, finding daylight where none seemed to exist and getting the ball to the end zone better than anyone else. Only this time, the rookie wasn’t Griffin, the Redskins’ transcendent superstar quarterback. It was Morris, the unassuming sixth-round draft pick who drives a 1991 Mazda 626 he calls his “Bentley.”

With Griffin still slowed by a knee injury suffered three weeks earlier, Morris, even more than usual, became the Redskins’ workhorse. Over and over, Griffin, 22, fed him the ball, and Morris, 24, ran to daylight. By the third quarter, Morris, plowing through defenders and hitting holes like vintage John Riggins, owned the Redskins’ single-season rushing record, bettering Clinton Portis’s seven-year-old record of 1,516, and by the end of the game, he had carried the ball 33 times for 200 yards, both career highs.

“Coming from where I came from, with no one expecting nothing from you, and to do this on this level, on this stage,” Morris said, “is just an honor.”

When it was over, Griffin and Morris took a moment to ponder what they had just done: Seven straight wins. The franchise’s first playoff berth since 2007. Its first division title since 1999.

“I was nine years old in 1999,” Griffin said. “I stand before you 22, and the Redskins the champions of the NFC East. . . . The Redskins haven’t won the division since 1999, and we came in and we did it in one year.”

Twenty years of angst, dating from the Redskins’ last Super Bowl team, had been building up to Sunday night’s kickoff, when it exploded across the region, from living rooms to the jam-packed sports bars to the raucous stands at FedEx Field.

In some sections of the stadium, fans stood the entire game, either to stay warm, or simply because their nerves would not allow them to sit. They watched the Redskins fall behind by a touchdown early, build an 11-point lead in the fourth quarter — on Morris’s 32-yard touchdown run — then hang on in the face of another Cowboys comeback.

With just more than three minutes left, the Cowboys and quarterback Tony Romo had the ball deep in their own territory, trailing by only a field goal. But on the second play of the Cowboys’ drive, Redskins linebacker Rob Jackson stepped in front of a Romo pass and intercepted it.

Less than a minute later, with the Redskins facing a critical third down, Cowboys defensive lineman Jason Hatcher was flagged for roughing the passer after hitting Griffin in the helmet, giving the Redskins a crucial first down — and leading to Morris’s final touchdown, a one-yard dive to ice away the game and push his rushing total from 199 to 200 yards.

“I’m not a star,” Morris said, cringing when that word was tossed at him in his postgame news conference. “I’m just Alfred. I’m still the same. I’m not going to change. I couldn’t change even if I tried.”

By late afternoon, the Redskins knew their game Sunday night was a do-or-die proposition. The Chicago Bears’ victory at Detroit had eliminated the Redskins from wild-card contention and simplified their mission: Beat Dallas, and the Redskins were in the playoffs. Lose, and they were out.

This was the final game of the 2012 NFL regular season, shifted a week earlier from a 1 p.m. kickoff to 8:20 p.m. by league and television officials who wanted it in prime time. That meant more obsessing and pumping-up for Redskins fans who hardly needed it.

At FedEx Field, fans arrived early, tailgated hard and screamed loud. The first “R-G-3!” chants took hold across FedEx Field during the coin toss. Three hours later, as they streamed out toward the parking lots and the warmth of their heated cars, the same chant could be heard echoing through the concourses.

That the Redskins would even be in this position — facing a win-and-get-in game in Week 17 at FedEx Field — would have been preposterous seven weeks earlier, when the Redskins staggered into their bye week with a 3-6 record two days before Election Day, with their fan base in revolt and their coach, Mike Shanahan, facing pointed questioning about whether or not he had given up on the season.

In the glow of FedEx Field’s lights Sunday night, through eyes full of mist, that 3-6 nadir deep in the fall looked like a lifetime ago. It is a new season now for the Redskins — playoff season — and no one will mind a bit if winter sits itself down and stays for a while.