The Kansas City Chiefs have stumbled to a rough start to the 2021 season, holding a 2-3 record through the first five games.Although the campaign is only more than a quarter of the way through, the Chiefs have had a troubling trend concerning the lackluster play of their defense. Kansas City have fallen to back-to-back losses, primarily due to their struggles defensively.Chiefs' lackluster defense could be their downfall this seasonThe Chiefs' defensive issues flared up on Sunday night in the blowout 38-20 loss against the Buffalo Bills. Star quarterback Josh Allen comfortably led the Bills offense with a strong performance, piling up 436 total yards with 8.1 yards per play.Allen lit up the Chiefs’ secondary for numerous big plays, leading him to post 315 yards on 15-of-26 completed passes with three touchdowns and held a 139.1 passer rating. The disappointing loss pushed Kansas City to allow a league-worst 7.1 yards per play, which is on pace to set an NFL single-season record, according to Pro Football Talk.Aaron Schatz 🏈@FO_ASchatzThe average DVOA of Kansas City's five opponents so far is 18.8%. No other team is above 11%. They've played BUF (1) CLE (6) BAL (8) LAC (11) and PHI (16).Average DVOA of their 12 remaining opponents: -1.3% (21st)#ChiefsKingdom footballoutsiders.com/stats/nfl/team…10:06 AM · Oct 12, 202110318The average DVOA of Kansas City's five opponents so far is 18.8%. No other team is above 11%. They've played BUF (1) CLE (6) BAL (8) LAC (11) and PHI (16).Average DVOA of their 12 remaining opponents: -1.3% (21st)#ChiefsKingdom footballoutsiders.com/stats/nfl/team…The current mark tops the previous all-time mark set by the New Orleans Saints, who gave up 6.6 yards per play in the 2015 season. However, the Chiefs are playing so poorly at a pace that will well surpass what the Saints recorded six years ago.The defensive struggles have been at the root of Kansas City’s struggles as the team is giving up a league-worst 32.6 points per contest. Their defense simply isn’t stopping any opposing offense, while placing tremendous pressure on star quarterback Patrick Mahomes to put up a high-scoring performance each week just to give his team a chance to win.Through the first five weeks, Mahomes leads the league with 16 touchdown passes, seventh with 1,490 passing yards, and holds a 106.1 passer rating. He’s on pace to record 51 touchdown passes, pass for 4,768 yards and throw 19 interceptions.Matt Derrick@mattderrick“They’re embarrassed by it … we all are,” says Andy Reid about losing by 18 points at Arrowhead.10:58 AM · Oct 10, 2021567“They’re embarrassed by it … we all are,” says Andy Reid about losing by 18 points at Arrowhead.The lack of defensive stability has pushed Mahomes into taking more risks with his passes to give his team a chance to compete. Beyond that, the Chiefs are in a rut with the rest of the AFC West pushing their way above them in the standings.The Los Angeles Chargers hold the early-season momentum, looking every bit the part of a playoff team with second-year quarterback Justin Herbert leading the charge. There is plenty of time for the Chiefs to turn it around, but the current outlook isn’t looking so bright.