The Bills won the opening coin toss. The decision to defer to the second half set up the Chiefs to take the opening possession, starting from the 30-yard line after a touchback.

In a game where ball control is crucial, Chiefs’ quarterback Patrick Mahomes’ first throw did not value it. On second down, he stepped up in a muddied pocket and floated a throw too high over the middle. The target to tight end Noah Gray was intercepted by Bills’ safety Taylor Rapp, who returned it to midfield.

The Chiefs’ defense started in compromised position, but pushed into third and seven. Bills’ quarterback Josh Allen tested Chiefs’ second cornerback Nazeeh Johnson then, playing man coverage on wide receiver Amari Cooper down the sideline. The 30-yard gain put Buffalo in scoring position.

The early-down defense continued to stifle Buffalo, but Allen beat the Chiefs on third down again, this time in the red zone. A missed tackle by safety Chamarri Conner set up the Bills at the three-yard line, where running back James Cook took the ball and scored on the ground. The Bills claimed an early 6-0 lead, fueled by Mahomes’ opening-drive interception.

The Chiefs’ offense failed to bounce back on the second drive, starting with a short incompletion that was tipped up at the line of scrimmage. On third down, Mahomes was unable to find a throw to attempt, and eventually came down for a sack by linebacker Terrell Bernard.

Buffalo continued picking apart the Chiefs’ defense on third down, finding a 15-yard completion on third down to keep the drive alive. However, Kansas City settled in and refused to allow a fourth-consecutive conversion on third down to start the game. Cornerback Trent McDuffie blitzed off the edge and forced Allen to throw an incompletion, putting the Bills in a punting situation.

From their own 12-yard line, the Chiefs picked at the Bills’ defense to give breathing room, converting a third and short with running back Kareem Hunt leaping over the line. Then, Mahomes found wide receiver Xavier Worthy in tight coverage; the rookie held on as he was sandwiched for a 31-yard gain.

In Bills’ territory, the Chiefs used a lineman-eligible play to move the chains on third and short; guard Mike Caliendo ended up catching a quick pass on a sprint out. On the next third down, Worthy made another big play — getting upfield after a catch over the middle to gain 14 yards and set up Kansas City 10 yards away from the end zone at the end of the first quarter.

Second quarter

Worthy finished off the possession that he owned with his play. He sprinted across on a shallow route, beating his defender to the pylon to give the Chiefs a 7-6 lead.

With a one-point deficit to work off, the Bills went to work converting two third downs before getting tight end Dawson Knox open towards the sideline for a 24-yard gain. That put Buffalo at the Chiefs’ 30-yard line. On second and long, Allen was hit as he threw by linebacker Nick Bolton, but the deep pass to wide receiver Amari Cooper was completed in bounds at the six-yard line.

On the next snap, Cook took a handoff, ran over Chiefs’ safety Bryan Cook and scored for the second time in the game. It gave the Bills a 13-7 lead.

The Chiefs’ offensive rhythm from the previous drive that didn’t get going on this possession. A first-down pass to Worthy was open, but he couldn’t complete the sideline catch in bounds. That was followed by an incompletion and a sack, most of the pressure coming from left tackle Wanya Morris’ side.

A strong punt return set up Buffalo well in Chiefs’ territory, but the defense stepped up its impact on this game. The pass rush forced a fourth and short, then Allen’s attempt to convert was intercepted by Chamarri Conner. The second-year safety returned it across midfield and to the Bills’ 40-yard line; the game-changing play set up the Chiefs’ offense with roughly seven minutes left in the first half.

Mahomes looked to take advantage of the turnover, finding Noah Gray on a screen pass to gain 14 yards and near the red zone. Then, tight end Peyton Hendershot brought down a scramble-drill catch in traffic to get inside the five-yard line. The Chiefs worked into third and goal, and Mahomes found the pay-off throw to Gray over the middle. The tight grab put the Chiefs back in front 14-13 with less than three minutes to go until halftime.

The Bills’ offense started and proceeded through the two-minute warning of the first half. A 21-yard catch gave the possession life, pushing into Chiefs’ territory. The quick passes continued into the red zone, working the clock to under 30 seconds. With 10 seconds left, the Chiefs made a tackle in bounds, forcing Buffalo to take the final timeout from the 15-yard line.

Allen’s final attempt at throwing a touchdown before halftime fell to the turf, setting up a field goal. A successful kick gave Buffalo a 16-14 lead at the intermission.

Third quarter

The Chiefs’ defense forced a three and out to begin the second half. A batted down pass by defensive end Mike Danna got the stop on second down, then the coverage was too tight for Allen to complete a downfield throw on third down. Buffalo was forced to punt.

The Bills’ defense matched the Chiefs’ three and out with its own. Buffalo stuffed a third-down run to force fourth down and a punt.

It was on the Chiefs’ defense to come back on the field and stop Buffalo again. The unit surrendered a third and short, then locked down a longer attempt to convert near midfield. A blitz heated up Allen, and forced an off-target incompletion. The Bills punted back to the Chiefs with under eight minutes on the clock in the third quarter.

Looking to get back in front, the Chiefs used wide receivers Mecole Hardman and DeAndre Hopkins to near midfield. From there, left tackle Wanya Morris set back the offense with a holding penalty. Mahomes could not dig out of that hole, and the Chiefs punted back to the Bills with less than four minutes left in the third quarter.

Buffalo got this drive off the ground and sustained it past midfield, converting a third and short with Allen sneaking from under center. That preceded a big catch and run by Bills’ wide receiver Khalil Shakir, who worked to the Chiefs’ 27-yard line as the third quarter concluded.

Fourth quarter

The Bills used another short pass to move inside the Chiefs’ 15-yard line, and punched it into the end zone when a blitz left Bills’ wide receiver Curtis Samuel wide open. The Bills took a significant, two-possession lead at 23-14.

Kansas City went to work on a do-or-die drive, still over 12 minutes left in the game. A gashing run by Kareem Hunt put the Chiefs deep into Bills’ territory, then Hopkins caught a quick slant at the sticks to set up first down at the 31-yard line. Wide receiver Justin Watson caught a route to the sideline to get into the red zone soon after.

Wide receiver Juju Smith-Schuster took a second-down screen and broke the first-down marker, getting to the five-yard line. Then, defensive pass interference set up the Chiefs at the goal line, where Mahomes rolled out and found Noah Gray in the corner of the end zone. That closed the Bills’ lead to 23-21.

Looking to ice the game, Josh Allen picked apart the Chiefs’ pass defense and moved the chains with his arm and legs. The clock ticked under four minutes with Buffalo in scoring position. The Chiefs pushed the Bills into third and short at the 26-yard line.

A stuffed run set up Buffalo to make a tough decision, and Allen made his coaches look smart. A dropback was disrupted, but Allen took off downfield, eventually running into the end zone on a 26-yard touchdown. The Bills seemingly put a dagger in the Chiefs with the play, going up 30-21 with over two minutes to go.

The Chiefs’ attempt to get a last-minute score did not go smoothly. Eventually, the offense faced fourth and long from their own 38-yard line. A deep attempt to Kelce was intercepted, wrapping up the Chiefs’ first loss of the season.

The Bills kneeled it out from there, and the Bills won 30-21

Special Teams

Kicker Spencer Shrader made his first kick as a Chief, making the point-after attempt to conclude the second-quarter touchdown drive. He made the second point-after kick later in the half, then the third in the fourth quarter.

Punter Matt Araiza has three punts through three quarters of play; none of the punts have been covered and tackled inside the 20-yard line.

Punt returner Mecole Hardman gained eight yards on a third-quarter return.

Cornerback Joshua Williams was flagged for being out of bounds on Araiza’s first punt, allowing five additional yards.