It’s Dallas Week in Washington, and after what has been mostly a decades-long hiatus for one of the more celebrated and combative rivalries in sports, the game this time has meaning far beyond nostalgia.

The Washington Redskins made certain of that by winning six in a row to set up a decisive, prime-time showdown for the NFC East title at home against their bitter adversary. The Cowboys, meanwhile, won three straight to climb back into playoff contention and nearly ran that streak to four before losing Sunday in overtime.

So cue the footage of George Allen mocking Tom Landry; Diron Talbert inciting Roger Staubach; Darrell Green chasing down Tony Dorsett; and LaVar Arrington ending Troy Aikman’s career.

“This game is going to be unbelievable,” said Redskins tight end Chris Cooley, who has played the Cowboys 13 times in nine seasons. “This is what should be one of the best rivalries in all of football, one of the top two or three games in all of football . . . but it hasn’t been Redskins-Cowboys where we both have great teams.”

In 2005, during his second season in the NFL, Cooley had the signature game of his career against the Cowboys in Week 15, when both teams arrived at FedEx Field with 7-6 records, chasing the New York Giants for the division lead.

By the time Cooley caught his third touchdown of the afternoon, the Redskins were well on their way to a 35-7 triumph and the third of five consecutive wins to close the season. Washington finished 10-6 by beating the Giants on Christmas Eve and the Philadelphia Eagles the following Sunday to secure a wild-card berth, while the Cowboys dropped two of three to miss the playoffs.

“That run we were on was fun, and it was awesome to come to work,” Cooley said. “And that’s what it’s like right now. It’s the same feeling.”

The Redskins own the longest winning streak in the NFC after Sunday’s 27-20 victory over the Eagles that included the return of Robert Griffin III. The rookie quarterback missed one game with a sprained right knee and watched from the sideline as backup Kirk Cousins directed a 38-21 win against the Cleveland Browns on Dec. 16.

When the Cowboys-Redskins rivalry was at its most contentious during the 1970s, Allen’s defensive charges often found themselves chasing the elusive Staubach the way defenders have been scurrying after Griffin this year.

Talbert also was particularly accomplished at needling the 1963 Heisman Trophy winner from Navy, frequently telling reporters that the best way to beat the Cowboys was to injure Staubach. The relationship between the players grew so hostile that they refused to shake hands during pregame coin flips, instead trading verbal barbs on the field.

Talbert never let Staubach or the Cowboys forget a 26-3 dismantling at the hands of the Redskins in the 1972 NFC championship game at RFK Stadium, when Allen famously inspired his team before the game by saying: “Just remember, 40 men together can’t lose.”

“First of all, this rivalry [began] long before him and long before me,” Cowboys owner Jerry Jones said last month, referring to his friendly relationship with Redskins counterpart Dan Snyder. “Secondly, it’s bigger than both of us put together. So having said all that, I just want to figure out a way for the Cowboys to beat the Redskins. Of course if it were the Giants or the Eagles, those are big too, but this Redskins thing is something that’s got more stories, and so storied.”

Staubach gained a measure of redemption against his nemesis in the final regular season game of his career, rallying the Cowboys from a 13-point deficit with less than four minutes left for a 35-34 win at Texas Stadium on Dec. 16, 1979. The victory, coupled with the Chicago Bears’ 42-6 win against the St. Louis Cardinals, sent 11-5 Dallas into the playoffs as NFC East champions while the Redskins, at 10-6, missed the postseason.

Dallas defensive end Harvey Martin tossed a funeral wreath into the Redskins’ locker room shortly after the win, the only time the teams played head-to-head in the final week to decide the NFC East.

The teams played in Week 15 in 1983, when both were 12-2. The Redskins trampled the Cowboys, 31-10, at Texas Stadium behind 89 rushing yards and two touchdowns by running back John Riggins and Art Monk’s 119 receiving yards.

Washington won its last 11 games that season, including the playoffs, to advance to Super Bowl XVIII, won by the Los Angeles Raiders. Dallas dropped consecutive games heading into the postseason, where it lost to the Los Angeles Rams, 24-17, in the first round.

In 1984, the Cowboys and Redskins met in Week 15 at Texas Stadium, again with major playoff implications. Trailing by 15 points at halftime, the Redskins forged ahead at the end of the third quarter, but the Cowboys reclaimed the lead on a 43-yard touchdown pass from Danny White to Tony Hill.

Midway through the fourth quarter, Riggins scored on a one-yard run to seal a 30-28 victory, and the Redskins moved into first place in the NFC East. Washington beat the Cardinals the next week to end the season with four straight wins and the division title. Dallas lost its final game and failed to qualify for the postseason.

“It’ll be special for everyone involved, and it’s the type of game you’ll remember for a long time,” Cooley said of Sunday’s encounter, whose kickoff time was moved to 8:20 p.m. to accommodate a national television audience. “It’ll be one of those games that can really change a franchise.”

Mike Jones contributed to this report.