Dak Prescott and Tony Romo grabbed most of the headlines for the Dallas Cowboys this week, but Ezekiel Elliott may emerge Sunday as the talk of the team.

The NFL's leading rusher has helped push the Cowboys atop the NFC East with a 4-1 mark. With Elliott improving every week, Dallas' second-ranked offense shows no signs of slowing down.

But the Cowboys haven't faced a test like the one they have Sunday, in which they take on the Green Bay Packers' top-ranked run defense at Lambeau Field. Through four games, Green Bay is allowing just 42.8 yards per game and 2.0 yards per attempt on the ground. And the Packers' defense has yielded just two runs of more than 10 yards — one for 14 and another for 12.

Yet Green Bay has established the imposing stats against sub-par rushing attacks, with the Detroit Lions ranking the best at 23rd in rushing yards per game. Opponents also have eschewed the run to take advantage of a vulnerable secondary, with top cornerback Sam Shields still sidelined by a concussion.

But the Packers' defensive line has shown it can disrupt plays from the get go. The unit has made a marked improvement from last season, in which it gave up 171 rushing yards on 20 carries to the Cowboys in a road win.

"Always excited for a challenge," Elliott said this week, according to the Dallas Morning News. "That's what players love. ... They're just physical, they're good in the middle, interior, got a lot of good players over there. So it's just going to be who's going to be the most physical."

As always for the Cowboys, establishing Elliott will help keep Prescott in his comfort zone of working the short-to-intermediate part of the field. If he's forced to throw downfield on obvious passing downs, Green Bay has an active pass rush that could fluster him.

Here are four other matchups that will define Week 6 in the NFL: