Yesterday was one of them.

The wunderkind, whose schemes were a major factor in the Giants' Super Bowl victory last season and in their sprint to the NFC's best record this year, finally was stumped by his old team. And the loss could turn into a fairly significant result in a conference race that had been dominated by the Giants.

Sure, Eli Manning had a weak effort in the swirling winds and frigid temperatures. And the Giants' running game wasn't nearly as effective as it had been throughout the season. But this was an afternoon built for a great defensive effort, a game in which a defense is capable of winning it on its own with a handful of big plays. But it was the Giants who gave up the big plays. For once, Spagnuolo didn't have the answers.

Brian Westbrook had a terrific game with a career-high 33 carries for 131 yards, including a 30-yard touchdown in the second quarter in which he sliced through a hole to his right and raced to the end zone. Westbrook added a 40-yard touchdown reception early in the fourth quarter, when he sprinted past a hopelessly overmatched Antonio Pierce.

And Donovan McNabb, whose career was left for dead after a tie with the Bengals and a loss to the Ravens in which he was benched, threw for 191 yards and a TD despite winds in excess of 20 mph.

In one stretch, the Eagles converted 12 of 13 third-down attempts, mind-boggling considering the Giants' previous defensive domination.

What happened, fellas?

"I thought we were well prepared throughout the week," Pierce said. "We had a good week of practice, regardless of what everybody else is going to say, and I thought we came out defensively ready to go."

But they weren't ready to go. And you have to wonder whether Pierce was distracted by his involvement in Plaxico Burress' accidental shooting and subsequent suspension and placement on the non-Football injury list. Pierce was questioned by police Friday, and he has been the target of speculation about whether he'll be prosecuted for his actions.

It didn't help that Pierce had one of his worst performances of the season, especially when it came to containing Westbrook. He insists the swirl of controversy surrounding Burress had nothing to do with it. When asked if it was difficult to be investigated one day and play a game two days later, he replied: "No."

What seemed far less debatable was how the Eagles' coaches took advantage of Spagnuolo's usually effective scheme. Here's how they did it: Knowing that the Giants could apply heavy pressure against McNabb and leave him vulnerable to sacks, the Eagles often used extra blockers - sometimes as many as eight - to contain the pass rush. McNabb was sacked only once, and that was when he tripped backing away from center.

The Eagles also used a quick-passing game to further offset the pass rush. Three-step drops by McNabb were the order of the day, and he employed the strategy to perfection. The Eagles averaged only 6.4 yards per pass, but the net effect was to keep the chains moving and to keep the Giants' pass rushers off McNabb.

"They had a lot of third-and-shorts, and we have to do a better job of tackling," Pierce said. "We have to do a better job of getting off the field."

Throw in terrific run-blocking from the Eagles' line, and the formula was complete. Westbrook ran extremely well between the tackles, and he broke his 30-yard touchdown late in the second quarter by following his blocking up the middle and then noticing an opening to his right.

The plan worked so well that the Eagles kept the ball for nearly 35 minutes, grinding out 331 yards and essentially negating the effects of the wind. Against the wind or with it, Philadelphia's decision to play small ball was the perfect strategy against Spagnuolo's attack-style defense.

It was particularly effective in the third quarter, when the game was essentially in the balance.

Despite being thoroughly outplayed in the first half, the Giants came to life with Kevin Dockery's 71-yard touchdown return of a blocked field-goal attempt on the final play of the second quarter. But the Giants did nothing after closing to 10-7. The Eagles kept the ball more than seven minutes on their first possession of the third quarter, and although they didn't score, they continued the tone they set early on. Westbrook's TD catch on their next drive sealed the verdict.

Time to panic? Of course not. When you're 11-2 and have wrapped up the NFC East title (thanks to the Cowboys' loss to the Steelers), there's no need for fans to freak out. But with Dallas, Carolina and Minnesota to finish up the season, it's certainly fair to wonder whether yesterday's defensive performance was simply an aberration or a crack in the armor.