The Kansas City Chiefs entered an important prime-time matchup, hoping to extend their undefeated winning streak against the Seattle Seahawks in Week 7 at Lumen Field. The defending Super Bowl champions served as the Chiefs' ideal measuring stick as they looked to continue their title run, but instead Kansas City suffered its first loss of the season.

Patrick Mahomes faced heavy pressure, especially as running back Kenneth Walker III looked human against his former team. The Chiefs struggled to find a rhythm in the passing and running game as the home crowd was loud all game and the Seahawks defense was aggressive and effective. Travis Kelce took another step forward in the history books, but the Chiefs still struggled to build momentum.

The defense gave up some big plays to superstar wide receiver Jaxon Smith-Njigba but held strong for most of the night. Nohl Williams made a clutch endzone interception to stop a scoring drive, continuing to prove himself as a starting-caliber defensive back in his second season. Ongoing issues with kicker Harrison Butker continue to haunt the team this season, as he added two more missed field goals.

Check out how some of Kansas City's stars fared in the Chiefs' loss to the Seahawks:

Stock Up: Travis Kelce

Kelce led all Chiefs receivers with four catches for 44 yards. He hit another career milestone, surpassing Tony Gonzalez's NFL record for career receiving yards, including both regular season and playoffs.

Stock Up: Nohl Williams

Williams held the Seahawks out of the end zone with a key goal-to-go play with less than a minute remaining in the second quarter. The interception provided hope before halftime, but Harrison Butker couldn't convert the field goal.

Stock Down: Harrison Butker

The veteran kicker had another tough game, missing two much-needed field-goal attempts. The second miss in the fourth quarter ended a promising drive that could have sparked a comeback.

Stock Down: Mansoor Delane

A 'Welcome to the NFL' game for Delane, as he was matched up against the best wide receiver in football, and he struggled on multiple plays. The reigning offensive player of the year delivered a highlight-reel performance against the highly touted Chiefs rookie.