Buffalo Bills keep their season alive as Josh Allen secures another win in Patrick Mahomes' backyard... while Chiefs QB's sideline fury shows tension is boiling over in Kansas City after four defeats in six games

It began shortly after a cluster of jets had roared overhead and a couple of golf carts carrying VIPs – including Time Magazine's Person of the Year, no less – had whizzed down into the bowels of Arrowhead Stadium. It began shortly before sideshow and ceremony gave way to football in Kansas City.

On the big screens at each end of the field, a short film: a compilation of clips showing Patrick Mahomes and Josh Allen at their brilliant best. The soundtrack included a line from one of their previous matchups: ‘Two incredible quarterbacks playing at a spectacular level,’ the announcer shrieked.

Then, as the teaser came to a close, the fireworks started and the stage was set: if anything was going to bump Taylor Swift and Travis Kelce off center stage, it would surely be these two and their battle for supremacy.

Mahomes has been the outstanding quarterback of the past half-decade – leading the Kansas City Chiefs to three Super Bowls in four years – but no one has troubled him here like Allen.

Before this trip , the Buffalo Bills star was the only quarterback to win twice at Arrowhead in the Mahomes era.

On Sunday evening, at the end of four fractious, controversial quarters, Allen had made it three wins in the Chiefs’ backyard.

One Kansas City supporter put it rather bluntly as the Bills QB put Buffalo in command early on: 'Mahomes is Allen's baby,' they fumed.

In truth, though, neither quarterback added many moments to their bulging highlight reels on Sunday. Neither quarterback produced many fireworks at all – at least with ball in hand.

The Chiefs offense was greeted with boos during a dismal first half; the Bills scored only a couple of field goals in the second half.

Instead, the lasting image of this 20-17 Buffalo win will be Mahomes on the sideline, spitting with rage in the direction of the officials. The quarterback threw his helmet to the floor and had to be restrained by several of his teammates.

Coach Andy Reid later called the incident 'embarrassing' for the NFL; a few supporters hurled shrapnel at the officials as they ran for the tunnel.

Really, their ire should have been directed at Kadarius Toney who in the dying moments was (correctly) punished for straying offside before he scored a go-ahead touchdown from Kelce's lateral.

It was a moment of genius from the tight end. Instead, Toney's error and Mahomes' fury rather encapsulated another night of frustration for the defending Super Bowl champions. One that could have significant consequences for both teams' hopes of reaching Las Vegas in February.

For the Chiefs, it's now back-to-back defeats and four losses in their past six matches. Their record now stands at 8-5. Kansas City's playoff hopes shouldn't hinge on this result: they remain destined to top the AFC West. But hopes of a bye are fading.

For the first time in his career, meanwhile, Mahomes is facing the prospect of a playoff game on the road.

He threw a crucial interception on Sunday's opening drive; his offense still isn't clicking. All while more and more eyes are trained on Kansas City. Kelce's performances don't seem to be suffering amid all the distractions and all the attention on his relationship with Swift.

The tight end was the Chiefs' leading receiver on Sunday and he very nearly turned defeat into victory on the team's final drive.

But all of a sudden, Kansas City look fragile and Mahomes' meltdown was the clearest indication that tension and frustration is starting to boil over.

Issues persist in Buffalo, too - despite this win. Victory here does at least keep their playoff hopes alive. According to ESPN, defeat would have put their chances of reaching the postseason at just 7 per cent. Victory gives them odds of around one in three.

So it represents a crucial first step. But nothing more. Stefon Diggs struggled for yards and Allen labored for much of the second half. Running back James Cook was a standout performer but the defense won the visitors this game.

'It wasn't the prettiest of wins. We all know that,' Allen said. 'But the defense played fantastic.'

Next week's clash with the Cowboys will prove another stern test of Sean McDermott's side. Here's hoping the Bills coach chooses his words more carefully when picking the bones out of this week's game. No comparisons with terrorist attacks would be a start. At least victory affords the Bills some positive headlines after a tumultous few days.

No such comforts for Kansas City. Chiefs fans can perhaps console themselves with the knowledge that a first-half sack on Allen ensured that on Monday, Big Macs will be buy-one-get-one-free around here.

If only a couple of wins came quite so easily.