The Giants had no such insight into the Panthers, allowing Steve Smith and DeShaun Foster to beat them at their own game in their own place.
Fox had Carolina prepared for everything New York attempted, rattling Eli Manning into four turnovers, and Smith scored two touchdowns to lead the Panthers to a 23-0 victory over the Giants in the first round of the NFC playoffs on Sunday.
"We challenged ourselves this week to know the Giants better than they knew themselves," said Carolina defensive tackle Brentson Buckner.
It was New York's first playoff shutout in 20 years -- and not much of a stretch for the Panthers (12-5) under Fox, who spent five seasons as New York's defensive coordinator before taking over in Carolina in 2002.
Fox still maintains close relationships with everyone from the Giants' front office to the cleaning crew and marked his return to the Meadowlands by staying one step ahead of everything his former team tried to do.
"It was strange -- they were in our huddle a little bit," said running back Tiki Barber, who was limited to a season-low 41 yards. "They kind of had us dissected and figured [us] out, and we couldn't get anything going consistently."
Not on offense, not on defense and not on special teams. Manning had his worst game of the season, the defense couldn't find a way to slow Smith or Foster, and the Giants muffed a punt while becoming the first home playoff team to be shut out since 1980, when the Los Angeles Rams blanked Tampa Bay.
The Panthers played nearly as well as they did in their Super Bowl season two years ago and advanced to a divisional playoff game at Chicago (12-4). The Bears won the teams' only meeting this season, 13-3 in November.
"Everybody may say we're a Super Bowl team -- we're not," Smith cautioned. "All we are is a one-win playoff team."
Carolina did it with a stubborn defense and a strong running game -- the same principles the Giants used this season to win their first division title in five years.
Foster ran for 151 yards by going straight at the Giants' depleted linebacker corps, kick-starting a running game that has been spotty all season. It was only his third 100-yard game this season -- the other two came against Atlanta, leading to questions if Foster could run on any other team.
"I don't think they thought we would really run the ball against them, but we established it early," Foster said. "It was just wide open. I got right to the second level, early. If I can get to the second level, I can make things happen."
But the play-making is usually reserved for Smith, and he didn't disappoint with 10 catches for 84 yards. He scored once on a 22-yard catch from Jake Delhomme, then ran a reverse in 12 yards for a second score.
"In my opinion, he should have been in the MVP voting with his regular season performance," Fox said. "I think he just proved his value to us today."
So did the defense, a staple of Fox's team.
Carolina intercepted Manning three times, then forced him to fumble late in the game in front of a nearly empty Giants Stadium.
Plaxico Burress was shut out and the Giants managed only 109 yards total offense.
"I didn't play well, and I made too many mistakes for us to win today," said Manning, who completed 10 of 18 passes for 113 yards. "It was not the way I wanted to come out and play. I look forward to coming back and getting better."
His struggles had a lot to do with the Panthers, who were insulted earlier in the week when Osi Umenyiora said Carolina had the second-best defensive ends in the NFL. The shot at Julius Peppers and Mike Rucker stung, and the entire unit responded.
Although Umenyiora and Michael Strahan combined for three sacks of Delhomme, Peppers, Rucker and the rest of the Panthers are the ones still playing.
"We were always overlooked. We don't know why that is," said safety Marlon McCree, who had two interceptions. "We've got the third best defense in the league. Sooner or later, we'll get the respect and recognition that we deserve."
Carolina forced five turnovers in all and kept New York's offense off the field. It allowed the Panthers to keep the ball a whopping 42:45.
"I believe we still have a lot to be proud of," Barber said. "We have no reason to hang our heads even though we showed the playoffs weren't what we were ready for."
Not on Sunday they weren't.
The New York crowd, so rowdy at kickoff, booed the Giants off the field after a frustrating first half. It continued most of the second half, until the crowd gave a sarcastic cheer after New York finally managed a first down -- one of only nine in the game.
"Anybody that likes the Giants that would have said in August they wouldn't take 11 regular-season wins, I think they'd be lying," said Manning's father, Archie, after the game. "You get over this and you go back and reflect on your season and go rest your body and your mind, and then you go back to work and do all the things you need to become a better player."
It was Eli Manning's worst performance since a four-for-18, 27-yard outing against Baltimore in his rookie season. Two months ago against Minnesota, he threw four interceptions, but balanced that by throwing a touchdown pass and rallying the Giants in the fourth quarter of a 24-21 loss.
A rally was a distant dream against Carolina as the Giants never mounted anything resembling a sustained drive and failed to get past the Carolina 39-yard line.
Peppers, who had a sack, said the game plan was to pressure Manning constantly.
"We got a couple hits on Eli early," Peppers said. "I think that kind of rattled him."