DeMarcus Ware intercepted the first pass of the season, one of six turnovers for a Dallas defense that also gave up 450 yards passing to Eli Manning and the New York Giants in the opener.
The Cowboys have been a study in defensive contradictions ever since.
They are the only team to keep Philadelphia out of the end zone this year, yet they've surrendered the first two 600-yard games for opponents in franchise history.
Dallas shut down one of the NFL's best rushing attacks to beat Oakland, then let Chicago score on the first eight possessions of a 45-28 loss.
"I feel like as a defense, we're just up and down a lot, and it's been like that for the last couple of years," safety Barry Church said. "That's one thing that we've got to get right. We've got to get our consistency level right where it needs to be where week in and week out we're a dominating defense."
Mostly the Cowboys (7-6) have just been embarrassing on defense this year.
Three teams have gone an entire game without punting this season — and two of them were facing Dallas. That doesn't even include a 49-17 loss to New Orleans when the Saints set an NFL record with 40 first downs.
The strangest thing is that the presence of defensive leader Sean Lee doesn't even seem to make that much of a difference. He strained a hamstring early in the loss to New Orleans and missed the next two games.
Without him, the Cowboys shut down the Raiders' running attack. With him, they couldn't get the Bears off the field.
"Every game that we've lost when we've given up a lot of yardage, it's big play after big play," said Lee, who expects to play Sunday against Green Bay (6-6-1) despite a neck injury that sidelined him against the Bears. "Games where we stop those big plays, or we cause turnovers, or we get off the field on third down, we play well. We really have to lock it down when it comes to third down and big plays."
The best example came early in the second quarter against the Bears. After the Cowboys punted in a 7-7 game, Chicago backup Josh McCown completed a 15-yard pass to Brandon Marshall on third-and-14 from the Dallas 38. The Bears scored five plays later and didn't trail again.
Dallas has given up at least five plays of 20 yards or longer in the past four games.
"This system is all built on the scheme," defensive tackle Nick Hayden said. "If people are not in the right gap, obviously they're going to hit us for big runs. Or if people are not in the right spots, they're going to hit us with big passes."
The Cowboys have faced questions about the scheme all season because they fired Rob Ryan and his risky, attacking style and replaced it with 73-year-old Monte Kiffin's more traditional — and supposedly safer — approach.
But Dallas has been juggling defensive linemen all season — 18 have played in at least one game — and the shuffling seems to have taken a toll on the pass rush. The Cowboys have just one sack the past two games.
"A big part of this scheme is the impact of four down guys getting to the quarterback," coach Jason Garrett said. "That certainly helps your pass coverage on the back end, and you know we've had guys in and out of our lineup. We've had a lot of new guys playing."
High-priced cornerback Brandon Carr couldn't stop Calvin Johnson one-on-one in a loss to Detroit, and the Saints' Drew Brees picked apart a zone. Neither zone nor man worked against Chicago because bigger receivers Marshall and Alshon Jeffery simply outjumped or outmuscled the Cowboys for the ball.
"You can't give up," Carr said. "There is no doubt. There is no lack of confidence. There isn't any questioning going on, just what can we do to win the next game."
Dallas could start by getting its defense off the field at least once.
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