Only one undefeated NFL team remains.

The Seattle Seahawks stumped the Kansas City Chiefs 20-3, giving Patrick Mahomes and Co. their first loss of the season.

The low-scoring game always favored Seattle, which took a 10-0 advantage into the break after a missed Harrison Butker field goal.

Kansas City struggled to gain momentum to cut into the deficit, with another Butker miss playing a role in the failed comeback.

Seattle improved to 4-3 with the result, while the Chiefs are now 5-1. Only the 6-0 Minnesota Vikings are flawless.

Let's analyze the game further with takeaways:

Jaxson Smith-Njigba stars again for Seattle

A matchup between two robust defenses needed to be broken open by stars. And there was no bigger star than Seahawks wideout Smith-Njigba. He went for nine catches on 12 targets for 150 receiving yards and a score.

Kansas City couldn't slow down his agility as he made elite catches all over the field.

It was a different story for Kansas City's receiver room, with tight ends Noah Gray and Travis Kelce each having 44 receiving yards to lead the way. Smith-Njigba was the difference maker once again for Seattle, though Emanuel Wilson had exactly 100 rushing yards and a score to play his part in the backfield.

Kenneth Walker III can't make an impact in his Seattle return

Last season's Super Bowl MVP couldn't show firsthand why Seattle should've kept him. Despite enjoying a stellar first season in Kansas City thus far, Walker III had very little to offer on the night.

He ran for just 36 yards on 14 carries, with a long of seven. He had four catches on five targets for 21 yards, also with a long of seven. Seattle's elite defense knew how to guard a former teammate.

Whereas Smith-Njigba broke open the game for his side, Walker III couldn't make that same impact for his new team. Xavier Worthy, on the other hand, had just three catches on six targets for 11 yards, so receiver is an upgradable position for Kansas City as the trade deadline nears.

Only one undefeated team remains

Not many would've expected Kyler Murray and the Minnesota Vikings to be the last undefeated team. But at 6-0 through Week 7, that's the case. Both Kansas City (5-1) and the San Francisco 49ers (6-1) saw their flawless starts snapped on Sunday.

Minnesota, led by Brian Flores' blitz-heavy defense, will see its record tested heavily in the coming weeks. Its next four games are at the Detroit Lions, vs. the Buffalo Bills, at the Green Bay Packers and vs. San Francisco.

The Vikings can only play who's in front of them, with their schedule including some less-than-impressive wins. It'll be interesting to see how far they can sustain the start.

The Atlanta Falcons handed the previously undefeated San Francisco 49ers their first loss of the season, winning 29-20 and dropping San Francisco to 6-1. Atlanta forced four turnovers and scored 13 points off those mistakes after the 49ers had committed just six turnovers through their first six games.