The Dallas Cowboys proved that their defense is for real on Thursday night, holding the best offense in the league to just 10 points. It was the Saints’ lowest point total since they scored just 6 against the Houston Texans in Week 12 of the 2015 season.

So what led to the Cowboys’ success?

One reason was that the Cowboys played more man coverage than normal. Dallas is a predominant zone-coverage defense. Their corners do not always follow receivers around the field. They prefer to take away big plays in the passing game with zone and allow their secondary to read route concepts, fly up quickly, and either break up the play or make an immediate tackle.

We thought that the Saints would try to exploit Dallas’ tendencies by bringing their receivers inside to generate 1-on-1 matchups against their linebackers. Defensive Coordinator, Rod Marinelli, probably anticipated this as well. The decision to play more man coverage and have their corners match up to receivers took away the Saints’ ability to generate favorable 1-on-1’s inside.

On top of that, the Cowboys’ secondary is good. Most of the time, Dallas’ team speed is credited to their front-7. But that secondary has proven to be very good in coverage all season. And much like the rest of the defense, they close on receivers and ball-carriers quickly.

Another main reason for the Cowboys success was pursuit. One of the staples of a Rod Marinelli defense is that everyone on the field flies to the ball. That’s not a skill as much as it is an attitude, and you see it regularly in Marinelli defenses.

The pursuit helped eliminate one of the key elements of the Saints Offense – the screen game. Time after time, the Saints were shut out of easy yards via the screen. The Cowboys recognized and reacted to these plays quickly. Take the below screen to Mark Ingram as an example.

Not only was Ingram hit right as he caught the ball due to the quick recognition, but the Cowboys finished with six players around the ball, including three defensive linemen.  That’s how you prevent big plays on screens.

This was a theme we saw all night, and it didn’t just occur against screens. Take this below Jet-Sweep to Alvin Kamara. This stop was set up by safety Jeff Heath, who got outside of Kamara and force him back inside to the Cowboys’ fast pursuing defenders.

Linebacker Leighton Vander Esch, who is an absolute ball-hawk with great open-field tackling skills, was there to make the tackle. If he missed, there were three other defenders ready to make the tackle. From Heath to the pursuit, that’s great team defense.

On the Cowboys’ first half goal-line stand, pursuit helped save what appeared to be a sure touchdown. On 3^rd down, Drew Brees dumped off a pass to Kamara in the flat, and it looked like he had plenty of room to maneuver for the score.

At this point in the play, it looked like there was no chance the Cowboys would prevent Kamara from the touchdown. Watch Jaylon Smith though.

Few linebackers in the NFL can move like that. Also, notice all of the white uniforms around Kamara. Consistent pursuit as a unit is a differentiator for a defense.

Another key driver of the Cowboys’ success was their defensive line. Their reputation definitely preceded them in this game, and it had Drew Brees playing fast from the first snap. We did not see the normally-precise Brees we are used to as a result.

Demarcus Lawrence and Randy Gregory have great speed off the edge, and that played a huge factor in this game (although Gregory’s mistakes overshadowed his positive impact). The rest of the defensive line stepped up and made some timely key plays, though.

The 4^th down stop on the goal line was largely due to the efforts of defensive tackle Maliek Collins and defensive end Tyrone Crawford. Both drew stalemates against their double-teams, allowing Jaylon Smith and Leighton Vander Esch to fill their gaps at the line of scrimmage.

The Cowboys created a wall in front of Kamara, enabling the stop.

Drew Brees’ game-ending interception was caused by the defensive line as well. Maliek Collins was again involved. He beat his man badly to get quick pressure in Brees’ face and cause the errant throw.

Brees was playing fast all night for a reason – he knew he had to in order to get the ball out. This significantly hampered New Orleans’ normally explosive attack.

It might sound cliché, but it took great team defense for the Cowboys to shut down the Saints and their #1-ranked offense. Dallas has the ability to hang with any team in the NFL because of their defense. They beat arguably the best all-around team in the league despite their offense basically laying an egg. If the Cowboys actually do get more consistent help from their offense, look out for this team come January.