Is Denver's deal for real?

Denver has the No. 1 ranked defense. The Broncos have allowed only one touchdownn in three games. Elvis Dumervil has six sacks. It's all good stuff. But two of the games have come against Cleveland and Oakland. Are they really that good? "I think they're really tht good," tight end Jason Witten said. " I think in the secondary they're as good as we've seen with Champ Bailey and then with [Brian] Dawkins back there. They're comfortable with what they're doing. That 3-4 gives you a lot of different looks. It's at home. They're getting a lot of sacks, a lot of pressure. It's going to be a tough matchup for us." And Tony Romo's response? "They run around," Romo said. "They do a lot of stuff defensively. They're a little like the Ravens in some ways with what they do. I think that's been a big reason why their team is off to the start they are."