The Dallas Cowboys quarterback has 1,693 passing yards and 14 touchdown passes from the first six games of the season, and has thrown just three interceptions.
Davis told the Eagles' official website: "I think one of the biggest things that Romo does is he extends the play.
"So we have to be great at finishing the broken play, as far as our coverage and staying attached in coverage. That's one of challenges, and I think the Denver game kind of showed that.
"They didn't stay attached all the time and all of a sudden, because Tony will see the field. He's got vision of the whole field and he'll find the guy that just [you] drift off of and we can't drift off our coverage."
The Eagles host the Cowboys, who currently top the NFC East.