​Kansas City Chiefs running back Kenneth Walker III was held to just 36 rushing yards in his return to Lumen Field in the Week 7 edition of Sunday Night Football.The Seattle Seahawks, where Walker spent four seasons and won Super Bowl MVP in last year’s title run, used elite defense and a punishing third-down offense to beat the undefeated Chiefs 20-3.The Seahawks’ defense made things difficult for the Chiefs, whose undefeated start to Patrick Mahomes’ return from knee surgery came to an end. Kansas City (5-1) had averaged an NFL-high 414 yards per game, but managed just 213 on Sunday night. The Chiefs never reached the red zone on offense – a first in a game started by Mahomes.While their defense dominates, taking care of the ball has been critical in Seattle’s (4-3) success in this up-and-down championship defense. After losing their last two games with seven combined turnovers, the Seahawks moved to 4-0 on the season when they give up one or fewer turnovers.Replacing Walker has been a full-team effort. With Zach Charbonnet still nursing a torn ACL from last season, Seattle has gone with Emanuel Wilson and George Holani as the primary ball carriers. Wilson rushed for 100 yards, and the Seahawks’ committee rumbled to 153 for the game.Wilson’s late touchdown run put Seattle up three scores in the final minutes of the fourth quarter. Charbonnet was taken off the physically unable to play list prior earlier in the week, but did not see any action against Kansas City.Kicker Harrison Butker missed two field goals, which also forfeited the Chiefs’ few scoring opportunities from Seattle’s side of midfield.Seahawks star receiver Jaxon Smith-Njigba totaled 150 receiving yards on nine catches for his sixth 100+ yard receiving game of the season. His 33-yard reception put Seattle in position to score first with a field goal from Jason Myers that capped a 15-play drive.Seattle entered Week 7 with the fourth-worst third-down offense at just a 32 percent conversion rate. The Seahawks were clicking as well as they have all season, as proven by their success converting 11 of 15 third downs against Kansas City.After several punts to start the game, Mahomes lobbed a pass over his intended target that landed in the arms of Ty Okada for Seattle’s eighth interception of the year. The turnover led to points for the Seahawks as Smith-Njigba, last year’s Offensive Player of the Year, hauled in an over-the-shoulder touchdown catch.Mahomes posted a season-low 165 passing yards on 19 of 33 completion.Darnold was also intercepted in the second quarter, but the Chiefs were unable to get points before the half. Butker’s ensuing field goal from 58 yards away was no good. As a result, the NFL’s most productive offense had been shut out at halftime.Darnold completed 20 of 28 through the air for 257 yards. He added 17 yards rushing on two carries that picked up first downs.In the third quarter, Kansas City nearly committed a second turnover as Mahomes fumbled on a scramble, but K