The Dallas Cowboys might be the biggest surprise of the 2016 NFL season, starting the season 4-1 without the injured Tony Romo. Now, the team faces its greatest test thus far when they visit the Green Bay Packers in Week 6.

Dallas has sole possession of first place in the NFC East after their most recent win against the Cincinnati Bengals. Having previously taken advantage of mostly subpar competition, the Cowboys had no problem beating the defending AFC North Champions, winning 28-14 after leading by 28 points in the fourth quarter. But even after defeating a formidable opponent, “America’s Team” still has its doubters.

The Packers, who are 3-1 after beating the New York Giants, are four-point favorites on Sunday. It’s not surprising that the Cowboys are underdogs on the road, but the betting line indicates that oddsmakers still give Green Bay an advantage over Dallas on a neutral field.

Aaron Rodgers is considered by many to be the NFL’s best quarterback. Dak Prescott has only made five starts, but the rookie has played as well as the team could have asked in Romo’s absence.

The league continues to wait for Prescott to look overmatched, but it’s looking more and more like that time will never come. The fourth-round draft pick is proving to be a first-round talent, setting a rookie record with 155 pass attempts with no interceptions. His 101.5 passer rating is good for eighth in the NFL, and he continues to get better with each game.

Since posting a 69.4 passer rating in the season opener, Prescott has had a passer rating better than 100.0 in every contest. He threw for multiple touchdowns for the first time in Week 4, and Prescott had the highest adjusted completion percentage among all quarterbacks in Week 5, according to Pro Football Focus.

Prescott has been able to thrive because he isn’t asked to do nearly as much as Rodgers. He’s playing behind arguably the NFL’s best offensive line with the league’s leading rusher in Ezekiel Elliot. Fourteen quarterbacks have thrown for more yards than Prescott, and he’s tied for 21st in passes of at least 20 yards. He makes his passes count, ranking seventh in yards per attempt and fourth in completion percentage.

The rookie will be facing a Green Bay defense that is coming off its best game of the season, but the Packers won’t be able to have the same kind of success against Dallas. Green Bay had four sacks against New York, putting pressure on Eli Manning all game. That will be difficult to do against the Cowboys’ offensive line and Prescott, who has been sacked just seven times in 2016.

Rodgers might not face much pressure either, considering he’s been sacked eight times in four games. Five of those sacks came against the Minnesota Vikings and the NFC’s best front seven. Dallas is tied for 17th in the NFL with 10 sacks, and they’ve relied on a secondary that’s exceeded expectations.

The Cowboys haven’t allowed more than 23 points in a game, surrendering 17 points or fewer in each of the last three contests. Cornerback Morris Claiborne might be the biggest reason, ranking fifth in the league in completion percentage against while allowing no scores. In Week 5, he limited A.J. Green to just 50 yards on four catches.

Claiborne could continue his strong play against the Packers and Rodgers, who hasn’t performed like an elite quarterback since 2014. Rodgers had another mediocre performance in Week 5, completing just 51.1 percent of his passes and throwing two interceptions. He should put up better numbers on Sunday, but Green Bay won’t have an easy time moving the ball.

The over/under of 47 is one of the highest on the Week 6 schedule, but with an overrated Packers offense taking on an underrated Cowboys defense, points might not be easy to come by. Prescott continues to prove his doubters wrong, and he has what it takes to pull off the upset in Lambeau Field.

Prediction: Dallas over Green Bay, 23-21