Eli Manning was fine. Brett Favre was better.

The Giants spent six days unsure whether Manning, who suffered a bruised throwing shoulder in last week’s opener, would be able to play against the Green Bay Packers. It turned out that the no. 1 concern shouldn’t have been whether their offense would have Manning. It should have been whether their defense could stop Favre.

Favre abused the Giants all day, completing 29 of 38 passes for 286 yards and three touchdowns, as the Packers won 35–13 to drop the Giants to 0–2 and give Favre 149 victories as a starting quarterback, the most in NFL history. The loss made it clear that unless the Giants get their pass defense fixed in a hurry, this is going to be a very long season.

The biggest problem yesterday was the aspect of the defense that new coordinator Steve Spagnuolo was supposed to fix: the pass rush. The Giants managed to sack Favre just once, when defensive end Justin Tuck tripped him, and there was no evidence of the intense blitzing that Spagnuolo’s defense was expected to bring. Most of the time Favre could spend as long as he wanted in the pocket, picking and choosing among the holes in the Giants’ secondary.

And the secondary had plenty of holes. Cornerback Sam Madison gave the Packers’ receivers big cushions that allowed Favre to complete short passes right in front of him. Cornerback Corey Webster had the opposite problem, playing too aggressively and giving up big plays, including a 46-yard pass from Favre to rookie receiver James Jones. Both Webster and Madison helped the Packers out with pass interference penalties.

Spagnuolo’s defense does have some wrinkles that look strong in design, if not in execution. The Giants’ strategy of dropping defensive linemen into coverage on passing plays appeared to fluster Favre on a couple of occasions, although on the play when that approach worked the best, Michael Strahan dropped what should have been an easy interception.

Between Favre yesterday and Cowboys quarterback Tony Romo last week, the Giants have now given up 631 yards and seven touchdowns through the air in two games. They’ve also given up 80 points. There’s no way around it: The Giants’ defense is a mess.

Despite the absence of the injured running back Brandon Jacobs, the offense wasn’t bad. Manning played through the pain in his shoulder and completed 16 of 29 passes for 211 yards, with one touchdown and one interception. Jacobs’s replacement, Derrick Ward, had a solid day, with 15 carries for 90 yards. Tight end Jeremy Shockey was the leading receiver, with five catches for 60 yards.

Still, for all of coach Tom Coughlin’s emphasis on discipline, the Giants continue to make stupid mistakes. Shockey negated one of his best plays, a 14-yard catch on a third-and-4, by spiking the ball afterward. The NFL implemented a new rule this off-season making spiking the ball on any non-scoring play a five-yard penalty, and Shockey apparently didn’t get the memo. Receiver Amani Toomer later got a foolish taunting penalty that moved the Giants from a promising third-and-goal at the 8-yard line to a hopeless third-and-goal at the 23. It’s an old story for the Giants: Coughlin’s disciplinarian style just isn’t getting through.

The worst news on offense was that rookie receiver Steve Smith left the game with a shoulder injury. In the first quarter, Smith lined up in the slot, ran a slant, and caught a 10-yard pass on third-and-2, doing for the Giants exactly what they hoped he’d do when they chose him in the second round of this year’s draft. But if the injury he suffered is serious, the Giants will have lost a player they hoped would add some spark to their passing game.

What the Giants lost yesterday was a game that could have positioned them in the middle of a crowded pack of second-tier NFC teams. They also lost whatever room for error they had heading into the game: If there exists such a thing as a must-win game in Week 3, the Giants have one next week against the Washington Redskins. Big Blue is winless through two games, and although there’s still time to right the ship, the Giants are at the bottom, looking up.

Mr. Smith is a writer for FootballOutsiders.com.