This is no time to get weepy, to become all sentimental about the Cowboys walking into the (fabled?) (historic?) (just awful?) Coliseum in Oakland for a final time. The next time the Cowboys play the Raiders, in 2021, the Raiders will call Las Vegas home, and the Black Hole will be part of NFL lore.

While the current editions of the Cowboys and Raiders fight to remain loosely alive in the playoff chase and avoid being labeled as the season's biggest disappointment (more on that later), I think it's unfortunate that Dallas-Oakland never lived up to expectations historically. Put Cowboys-Steelers and those three Super Bowls aside. Cowboys-Raiders is the greatest rivalry that never happened.

The battle between America's Team and the Commitment to Excellence boys should have been a January staple when the Super Bowl era began. It's almost a miracle, given how each franchise lived near the top of its conference for about 15 years, that they never met for the ultimate prize.

The Cowboys and Raiders played in half of the first 18 Super Bowls, winning five Lombardi Trophies without crossing paths. Consider the following:

If Bart Starr comes up short on that sneak and the Cowboys preserve their Ice Bowl lead, Dallas plays Oakland in Super Bowl II.

Oakland falls to Baltimore in the 1970 AFC title game; otherwise the Raiders meet the Cowboys in Super Bowl V and there is no Blooper Bowl.

Minnesota plays Miami in Super Bowl VIII in Houston. The Cowboys and Raiders were their conference championship victims.

The Raiders fall to Pittsburgh (not the Immaculate Reception game but a close 16-10 defeat), allowing the Steelers to play Dallas in the Super Bowl for the first time after the 1975 season.

In 1977, the Raiders lose to Denver in the AFC title game. So the Cowboys run over the Orange Crush and Craig Morton instead of facing Ken Stabler and the defending champs in New Orleans.

And in 1980, Danny White's first of three NFC Championship Games ends in defeat at Philadelphia. The Eagles become the Raiders' second Super Bowl victim.

This is how these franchises built their reputations, through sustained greatness. Each now lurks in the shadows of NFL relevance. You know the Cowboys' recent sordid history. No NFC Championship Game appearances in 21 years, and barring a five-game winning streak to close the season along with some good fortune mostly in the form of two Atlanta Falcon defeats, that streak runs to 22 years next month.

The Raiders are 15 years removed from their last Super Bowl and AFC Championship Game appearances. These extended runs were once unthinkable for Cowboys and Raiders fans. Now they have become understood if not accepted as 7-6 Dallas wrestles with 6-7 Oakland in a loser-go-home Sunday night national telecast.

Among last year's playoff teams, only the New York Giants and the Houston Texans, each sporting massive injury lists, have worse records than the Cowboys and Raiders (Miami is tied with Oakland). It has been a season of disappointment for both although the prize remains in sight, even if it's off in the distance.

The Cowboys have the boost of knowing that Ezekiel Elliott returns before their Christmas Eve date with the Seattle Seahawks. Three straight wins could do a lot to right the wrongs of the miserable three-game skid that began the non-Zeke era.

But the Raiders, humbled as they have been this season with Derek Carr failing to play up to the level of his $125 million contract that includes $70 million in guarantees, present more of a real challenge than the Redskins and Giants, both staggered by injuries, ever could.

All-Pro pass rusher Khalil Mack is getting his weekly sacks, the well-traveled Marshawn Lynch has picked up his game of late with 162 rushing yards on nearly 7 yards per carry the last two weeks, and the Raiders' leading receiver is a scary reminder for Cowboys fans -- tight end Jared Cook, who caught Aaron Rodgers' last-gasp playoff pass on the Dallas sideline in January.

Far removed as these clubs are from their Super Bowl pasts, they still have much at stake Sunday in one final Cowboys ride through the Coliseum. Dallas hasn't won a game there since they were, in fact, Super Bowl bound in 1995. Erasing that streak might be a fitting way to leave the Black Hole once and for all.

Twitter: @TimCowlishaw