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They are not spectacular. They are not flashy. They do not blow you away and are far from perfect. But if you don't think these Dallas Cowboys are for real, you are a fool.

And the reason they are isn't just the usual star suspects. It's not just because of the dominance of the NFL's rushing leader, Zeke Elliott, or the clever play of resurgent quarterback Dak Prescott. Dallas is legitimate because of a fast, nasty defense that just manhandled one of the great offenses of all time. Held it to 176 yards of offense. Punched it in the mouth, just like the Cowboys said they would.

Dallas has won four straight games, and the victories haven't been over a bunch of stiffs and bums. It beat Philadelphia on the road, then Atlanta, followed by Washington and now New Orleans. The Saints had previously won 10 consecutive games.

What we saw in the Cowboys' 13-10 victory on Thursday night against the Saints was the culmination of an evolution. We saw Dallas go from awful early in the year, to a curiosity, to a team that will be one of the toughest outs should (when) it makes the playoffs. And the reason is that Gloomsday Defense, the modern incarnation of its Doomsday cousin.

No, the Cowboys aren't without flaws. Prescott is still sometimes too careless with the football, and the team overall makes too many dunderheaded mistakes, like when Randy Gregory ran into the punter, leading to a penalty and setting up the Saints' only touchdown.

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Still, the Dallas defense is smart, nasty and just shut down one of the best offenses—and quarterbacks—in football. This was a statement game not by Prescott or Elliott, but by that defense.

Drew Brees started 0-of-4 in passes for the first time in his career, as the Fox broadcast pointed out. His 39 passing yards were his fewest in a first half as a Saint. That's 13 years.

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It was the first time the Saints were shut out in the first half—in this case 13-0—in 72 games. It ended the longest such streak in the NFL. The 59 total yards in the half were the fewest since 2002 when Aaron Brooks was the quarterback.

How did the Cowboys do it?

What makes them unique isn't just how fast they are; it's how they use that speed. They chase after ball-carriers as well as any team in football. They caught Alvin Kamara, the slipperiest runner in football, several times from the backside on plays that Kamara would normally break.

"The one thing about our defense, what makes us elite, is we run to the ball like no other team," Dallas linebacker Jaylon Smith said on the broadcast after the game.

Before the game, defensive lineman Demarcus Lawrence provided a hint of things to come in this contest. He said what the Cowboys were going to do: punch the Saints in the mouth.

"They're going to have to match our intensity," Lawrence told reporters. "S--t, for 60 minutes straight. If you hit a motherf--ker in the mouth and then they ain't doing what they're regularly doing, putting up 50 points, they start to get a little distressed. Now you got them where you want them at, and then you f--king choke their ass out."

So, there's that. And Lawrence and the defense made his words come true.

The Cowboys punched, and the Saints went down. For the first time all season, Brees looked confused and a step behind. For the first time all season, every offensive play was difficult.

The Cowboys haters (and I was one of them) will say they are still the same ol' Cowboys. There are still disbelievers in Prescott. That's fine. Feed your hate. Let it grow as the Cowboys become a fully operational Battle Station.

No, these Cowboys aren't perfect.

Yes, these Cowboys are for real. Thanks to that defense.

Which will punch you in the mouth.

Mike Freeman covers the NFL for Bleacher Report. Follow him on Twitter: @mikefreemanNFL.