This wasn't the first and won't be the last game the Giants' defense costs them

NEW ORLEANS -- The New York Giants lost a game to the New Orleans Saints on Sunday in which their quarterback, Eli Manning, threw six touchdown passes and no interceptions. A regulation game in which they had a positive turnover differential, committed half has many penalties as their opponent did and held a seven-point lead in the final minute. It takes a special kind of defense to lose a game like that, but the Giants' defense is riddled with holes and very often doesn't look as though it knows what it's supposed to do.

This is not a problem that's going to get better in 2015. Yes, they'll eventually get Prince Amukamara back from injury to shore up the secondary. No, I don't think the ankle injury that kept Jon Beason out Sunday is season-threatening. And we all know Jason Pierre-Paul is preparing to play in Week 10.

But the Giants were blowing fourth-quarter leads to quality quarterbacks in Weeks 1 and 2 with Amukamara in there. Beason is a diminished player because of his chronic injuries. And no one knows for a fact Pierre-Paul can play in Week 10 (or at all), or what he'll give them when and if he does return.The Giants' problems on defense are extensive. They don't rush the passer. They don't cover well. They miss a ton of tackles. They've been living on turnovers and hanging on against the likes of Matt Cassel and Kirk Cousins. But as Tony Romo andMatt Ryan showed earlier this year, and Drew Brees' seven-touchdown performance absolutely shouted all day Sunday, a quality quarterback can do basically anything he wants against this undermanned unit.

In two weeks, the Giants have to play Tom Brady and the Patriots. Brady is playing quarterback right now about as well as anyone ever has. I'm not saying he will (or even could) do better than Brees did against the Giants on Sunday. I'm just saying this is a defense that made Colin Kaepernick feel comfortable in the pocket. Someone like Brady is going to look at Giants tape and see target practice.

"Find the words. Frustrating," Tom Coughlin said about his defense Sunday afternoon. "You want to explode, but that's not going to help, so you're trying to figure out how you can help."

It sounds crazy, given where they rank statistically, but the Giants' coaching staff has done a commendable job with this defense this year. They have major personnel deficiencies at every level. They have a collection of rookies and backups and undrafted try-hard types who give outstanding effort every week. They're opportunistic, meaning that not only do they seek and force turnovers but they tend to do something with them. They have three defensive touchdowns so far. So even though they're a net liability, they do make a contribution. That's commendable.

But over the course of a full season, this defense is a liability. It cost them in the fourth quarter in Dallas, at home against Atlanta and all day in New Orleans. It cost them against the 49ers, though Manning rescued that one with his own late heroics. It's almost certainly going to cost them again, against a December schedule that features four teams with a combined current record of 18-9.

"We've been able to shut the door a couple of times this season, but obviously we didn't do that today," rookie safety Landon Collins said.

Too often, the Giants' defense leaves the door way too wide open for the opposing quarterback. When that quarterback is someone like Brees ... well, you see what happens. The Giants remain in first place and could certainly grind their way to an NFC East title. But as long as they keep playing defense the way they have so far, it's going to be a rough ride getting there.