When a footballer’s boots are among the pre-match talking points it should normally be a sign that subplots are scarce: the opposite will be true when Xherdan Shaqiri walks out in Kaliningrad. The Switzerland forward will be sporting footwear that, on his right heel, displays the stitched flag of Kosovo. He is far from the only member of the team to profess that allegiance and it has raised the temperature of a fixture that has looked pivotal to both sides’ World Cup hopes ever since the draw was made.

“If he loves Kosovo so much and decides to flaunt the flag, why did he refuse a chance to play for their team?” asked Aleksandar Mitrovic when Shaqiri’s choice of boot – for balance, a Swiss flag is displayed on his left shoe – was raised last week. That Mitrovic decided to fire back told enough of a story. Any excuse for needle between Kosovo and Serbia, which refuses to recognise the former as an independent state, tends to be seized upon in a flash and Shaqiri had made his own feelings public by posting an Instagram picture of his boots last month. The reaction online and in the Serbian media – “Provokacija” (provocation) being a prominent and time-honoured theme – was outrage but Shaqiri will, at least, be able to count on strength in numbers if bad blood spills on to the pitch.

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Granit Xhaka and Valon Behrami are the other likely Switzerland starters with Kosovar heritage; all of their families left Kosovo, which would be ravaged by war between local forces and present-day Serbia, in the late 1980s and early 1990s, and the result is a very modern European football configuration. Before Kosovo was recognised by Fifa and Uefa in spring 2016, and allowed to play competitively, its far-flung sons were its loudest voice on the international sporting scene. Switzerland, with its estimated 200,000 Kosovar residents and wealth of footballing talent from the country, was supported in lieu of their national team.

🔥😱😍👌🏻❤️ A post shared by XS (@shaqirixherdan) on May 23, 2018 at 10:29am PDT

That was again broadly the case in Kosovo on Sunday, when Steven Zuber’s equaliser against Brazil brought cheers in bars from Pristina, the capital, to Gjakova in the west. The goodwill remains strong although it would be a stretch to say the country has, as a result, been consumed by World Cup fever: in 2014 big screens were erected in the centre of Pristina and large crowds watched the action unfold in Brazil; this year the excitement is reported to have lowered a notch or two and perhaps that is because Kosovo is increasingly confident in its own football skin. The national team finished bottom of their World Cup qualifying group but – now managed by a veteran Swiss coach, Bernard Challandes – they can call on a swelling tide of eligible second-generation talent and look well placed to improve dramatically over the next five years. It all means that, while the sporting relationship with Switzerland remains strong, there are other parties involved now too.

Nevertheless the pride will be boundless if Shaqiri, Xhaka or Behrami play decisive roles in Serbian misfortune. All three were solicited by Kosovo’s FA in 2012 to sign a petition pledging support to its bid for a legitimate national team; all are known to have done so and as Mitrovic suggested there were, at various times and with varying degrees of optimism, suggestions any or all of them may be persuaded to change international allegiance.

“What if the coach of Kosovo wants me as the captain? Of course, I am thinking about it then,” Shaqiri said during Euro 2016, although it seemed more like a thinly veiled attempt to sharpen Swiss minds about his seniority within their own setup. Xhaka then stated he would “do whatever I can” to play for Kosovo although, shortly afterwards, Fifa confirmed that no switch would be possible.

Now they can, at least, strike a blow for two nations at once. The noise and rhetoric around the fixture is unlikely to abate in its buildup. Serbia are well represented in Russia, where their sizeable contingent of fans is augmented by the goodwill of many locals. After Serbia’s win over Costa Rica in Samara on Sunday, sporadic outbreaks of “Kosovo je Srbija” (Kosovo is Serbia) could be heard coming from bars in the city, Russian fans joining in with their visitors. The atmosphere on Friday is likely to be partisan; there is pride at stake along with, in a far more practical concern, what is almost certainly a single place in the last 16 alongside Brazil.

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“Maybe people don’t know everything about us – but I think that is a positive because it means there is not a lot of pressure on us,” Shaqiri said on Sunday, not long after delivering the corner from which Zuber scored. He meant that Switzerland are seen as dark horses in the bigger picture, but the demand for a result against Serbia is rather more immediate and widespread. Perhaps the Swiss are not highly favoured but on Friday, certainly for those watching in Kosovo, the boot will be on the other foot.