Dallas defenders Jay Ratliff, left, and DeMarcus Ware, right, here pressuring Miami quarterback Trent Green last month, may be key to the Cowboys chances against the Patriots on Sunday.

MCT / Ron T. Ennis

FOXBORO — The Dallas Cowboys’ offense has put up numbers on par with those of the New England Patriots so far this season, but the Dallas defense isn’t too shabby either, and will have the unenviable task of trying to slow down Tom Brady & Co. come Sunday afternoon.

“They’re very active,” Brady said, sounding a lot like Pats coach Bill Belichick. “They’ve got a great front seven. They have playmakers in the secondary; I think they lead the league in turnovers. They do a lot of things really well. They strip the ball. They intercept balls. They rush the passer. They stop the run.”

On paper at least, the Cowboys are nearly as balanced as New England: Dallas has the number-one ranked offense in the NFL after five games, gaining 429 yards per outing, and their defense is eighth overall in the league, allowing just over 285 yards.

The Patriots’ offense is second to Dallas’, and the ‘D’ is second overall in the league as well.

Belichick teams have gone against Wade Phillips’ squads on numerous occasions, most recently in the AFC Divisional round last January, when Phillips was San Diego’s defensive coordinator.

Whenever he faces a Phillips-coached unit, Belichick knows it will be fundamentally sound.

“Wade has had a great deal of success wherever he’s coached defense, whether it be as a head coach or a coordinator. His teams are very sound. They pressure quite a bit and they don’t make many mistakes,” Belichick said.

Like New England, Phillips’ Cowboys play a 3-4 defense, though it is a different type of 3-4 than the Patriots’. The Pats’ down linemen are focused on gap control, while Dallas players have the go-ahead to penetrate and be more aggressive as rushers.

And weakside linebacker DeMarcus Ware is often down on the line as well, making the ’Boys even less of a traditional 3-4 system.

Belichick said this week that Phillips uses Ware in a way similar to how he used Shawne Merriman with the Chargers.

“I’d say it’s similar, but I really see Ware playing about the way he played last year. He plays outside on the 3-4 and he plays end on a 4-3, or in their 4-2 or sub package,” Belichick said of Ware. “He’s tough off the edge. He’s tough in pursuit.”

It would seem that Ware, a third-year player chosen by Dallas 11th overall in 2005, has the type of versatility that Belichick favors; the New England coach spoke very highly of the 6-foot-4, 252-pound Pro Bowler.

“We saw a lot of him in college when he came out in the draft. I thought he was probably the best player in that draft [Merriman was taken one pick after Ware],” Belichick said.

“He’s certainly a dynamic player in all phases of the game: he can rush, he can cover, he can play the run, he has power, he has speed. He’s hard to knock off his feet. He’s quick. He’s a force.”

Ware has 4½ sacks and 11 quarterback hurries; he also has 19 tackles.

There are weaknesses to exploit, however. Though the Cowboys are allowing just over 80 rushing yards per game and have not yet had a runner go over 100 yards against them, they are in the bottom third of the league on first down, traditionally a running down, giving up 5.56 yards per first-down play. That is 23rd in the league.

Those issues carry over to third down. While overall Dallas is allowing opponents to convert 38.1 percent of third-down tries, when that number is broken down, it becomes clear that getting in shorter third-down situations is favorable.

When facing third-and-6 or less, the Cowboys defense is giving up the first down just over 50 percent of the time (13-for-25). On third-and-7 or longer, that average drops to 29 percent.

smanza@projo.com