Many NFL fans probably expected the New England Patriots to be one of the remaining undefeated teams as this season went on, but it is unlikely many guessed the San Francisco 49ers would join them.
The Carolina Panthers are another surprise success story, while the Dallas Cowboys have taken a turn for the worse over the last few weeks.
Here we look back at the biggest headlines from Week 6 and the impact they will have heading into Week 7.
Are quarterback changes coming to NFC South?
Jameis Winston threw five interceptions and fumbled twice in the Tampa Bay Buccaneers' loss to the Panthers as they dropped to 2-4, but head coach Bruce Arians made it clear the team are not considering replacing him — yet.
"No. I look at the reasons why. What happened?" Arians told reporters, noting the team's battered line was partly to blame for the ugly outing. "If it happens again, yeah, it'll concern the hell out of me."
Similarly, the Panthers may not be looking to put Cam Newton back in and bench Kyle Allen after the second-year quarterback helped pull the Panthers out of their 0-2 hole to start the season. In fact, Allen could keep the starting job as long as he keeps winning, though coach Ron Rivera remained tight-lipped on the subject Sunday.
"I'm not going to worry about it," Rivera said. "I'm not going to speculate on anything until I have to address that. So until then, we're going to stay in the now, stay in the focus of what we're doing right now. As far as I'm concerned, we're not going to deal with the question until it is time. And when the time comes, I will address it."
An ESPN report on Monday said Newton is almost ready to resume practicing. Both Carolina and Tampa Bay will be on their bye in Week 6, so stay tuned.
Mariota era could be winding down in Nashville
Quarterback controversy struck Tennessee as the Titans pulled the second draft pick of 2015 in the team's shut-out loss to the Denver Broncos for veteran backup Ryan Tannehill. Marcus Mariota was sacked three times and completed just seven of 18 passes for 63 yards with two interceptions before getting the hook. Tannehill was better, completing 13 of 16 passes for 144 yards with a pick.
As for who will start Week 6 against the Los Angeles Chargers, the team expect to have an answer by Tuesday.
"I think a decision will be made this evening, or tomorrow, and we’ll let everybody know — we’ll let the players involved know, and let the team know and then let you guys know," coach Mike Vrabel told reporters. "I just want to make sure we are going through everything that we need to go through and what we are doing offensively, and not use the emotion of the game to make a decision."
Can 49ers make statement by extending win streak?
With the Patriots on a bye, the Niners have a chance to match their perfect 6-0 record after dismantling defending NFC champions the Los Angeles Rams on Sunday. The 49ers held Los Angeles to 3.3 yards per play, which is the lowest average in Rams franchise history, and quarterback Jared Goff had his worst performance to date as he completed 13 of 24 for a career-low 78 yards.
San Francisco have shined as arguably the most surprising team this year after the 49ers managed just four wins all last season. Now 5-0 for the first time since 1990, the Niners may only gain momentum with matchups against the Washington Redskins, Panthers and Arizona Cardinals looming.
Falcons giving Quinn until bye week to turn things around
Atlanta will host the Rams and Seattle Seahawks in back-to-back games before getting some rest Week 9, and after a 1-5 start just two and a half years removed from their trip to Super Bowl LI, the team are running short of patience.
NFL Media reported that Falcons owner Arthur Blank wants to see progress over the next couple of weeks "or changes could come," with the fifth-year coach as one of them. Dan Quinn already fired all three of his co-ordinators before the season started, so the blame would have to fall on him.
Jay Gruden may have been the first coach to get the axe, but he certainly will not be the last, and it appears Quinn has two weeks to save his job.
Amari Cooper's potential absence could have big implications
Cowboys receiver Amari Cooper's status for Week 6 reportedly "is in serious question" after he was diagnosed with a bruised thigh suffered in Sunday's loss to the Jets. Dallas coach Jason Garrett said the team are taking his injury day by day, but could not guarantee his availability.
The ailment could not come at a worse time considering Dallas have dropped three straight games and face a key game in Week 6 against NFC East rivals the Philadelphia Eagles. A fourth consecutive loss could officially put Garrett on the hot seat, though Cowboys owner Jerry Jones insisted it has not come to that yet.
"I haven't even glanced there in my mind about long-term future," Jones told reporters. "The big thing I want to say is it's not just him. This is across the board, and that had a lot of input out here tonight to get in that spot."
Garrett, who is entering the final year of his contract, reiterated that getting the team to the top of the NFC East is his main concern.
"I'm focused on doing my job as well as I can do it," Garrett said, per The Athletic.