The NFL's group of unblemished teams is down to an elite quartet.

After five weeks, the Green Bay Packers, Seattle Seahawks, Pittsburgh Steelers and Tennessee Titans are the last remaining outfits yet to be dealt a defeat this season. But the road for all of them is about to get significantly more difficult, with the Steelers facing the 4-1 Cleveland Browns on Sunday and the Packers take on Tom Brady and the Tampa Bay Buccaneers. Even if all of the groups remain perfect through this week (the Seahawks are on a bye), there's guaranteed to only be one AFC unbeaten team left standing after Week 7, when the Titans host the Steelers. 

With that in mind, we asked NFL reporters and columnists from USA TODAY Sports: Who will be the last unbeaten NFL team standing in the regular season?