You could say it's the Giants defensive front seven against Eagles quarterback Michael Vick. Maybe it's the Giants, with a depleted receiving corps, finding a way to complete passes against the talented Philadelphia secondary. Maybe it's the Giants punt coverage trying to control DeSean Jackson. Or left tackle Will Beatty of the Giants facing the biggest test of his career when he lines up across from Trent Cole of the Eagles.
Maybe it's the Giants against their own demons. New York has lost six straight to Philadelphia, including last season's epic fourth-quarter collapse, blowing a 21-point lead in the final eight minutes.
You could say all of those. I think, though, that the most critical element for the Giants on Sunday is somehow finding a way to control the explosive Philadelphia passing attack with their injury-ravaged secondary.
The Eagles live for the big play on offense, and they have a core of receivers who can provide it. Wide receivers Jeremy Maclin, DeSean Jackson, Jason Avant and former Giant Steve Smith are a talented group, Brent Celek is an excellent tight end and running abck LeSean McCoy is a pass-receiving weapon out of the backfield.
The Giants, without Terrell Thomas for the season and waiting for first-round pick Prince Amukamara to return from a broken foot, have surrendered more than 300 yards passing to both Washington and St. Louis, offenses far less capable than Philadelphia's.
Aaron Ross, Thomas's replacement, was targeted repeatedly by St. Louis. The Giants, with Ross starting and Antrel Rolle moving to the slot against three-receiver sets, have also had some communication breakdowns during the first two games.
To have any chance on Sunday the Giants must limit Philadelphia's quick-strike capability. Much of that will have to come from the pass rush, but the secondary also needs to be better than it was in the Giants' first two games. If the Giants allow the Eagles to turn Sunday's game into a track meet, they won't be able to keep up.