For Sparta Prague there is plenty riding on Wednesday’s meeting with Brest. Nobody knows exactly what kind of tally will secure qualification for the Champions League knockout stages but a win would probably put them within touching distance of February’s playoffs. This is already their best European performance for more than two decades; they play in one of the most rapidly improving leagues, a fact that would be borne out if they emerge breathing from the sprawling 36-team bulk.

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So it is far from ideal that their buildup has been troubled and, from another angle, symptomatic of a problem football stadiums across the continent cannot shake off. An inquest was inevitable when Sparta fell to a 3-1 home defeat against Banik Ostrava on Saturday, leaving them 10 points shy of the league leaders, Slavia, and severely minimising the chances of a third straight title. But nobody could have expected the tensions around Serbia, Albania and Kosovo to fuel a controversy that has sent the gossip machine into full swing since then.

It surrounds the absence of Veljko Birmancevic, the influential Serbian forward. A fortnight ago Birmancevic was giving Manchester City sporadic headaches at the Etihad before Sparta were seen off comfortably in the second half. Now he was nowhere to be seen, ostensibly owing to a groin problem communicated publicly before Banik’s visit. Local reports painted a different picture: the former Malmö and Toulouse player had, they said, been left out after a row with the club’s sporting manager, Tomas Sivok.

Sparta’s ultras made clear their allegiance in any dispute with a banner reading “Support for Birma” that appeared in the Letna stadium stands during Saturday’s game. But the rest of their message was less wholesome: a number of accompanying standards bore images of Kosovo, over which Serbian flags and the message “No surrender” were superimposed.

That is distasteful enough given Kosovo declared independence from Serbia in February 2008 and scars from the bloody war of the late 1990s run deep. Such messages spring up with alarming constancy despite Uefa’s attempts to act. As recently as September, a Women’s Champions League match in Romania between Farul Constanta and the Kosovan club Mitrovica was interrupted when Serbian flags appeared in the stands.

But there was another dimension, whether intended or not, to the Sparta fans’ actions. The Kosovo internationals Albion Rrahmani and Ermal Krasniqi are important members of their squad; so are Indrit Tuci and Qazim Laci, who represent Albania. More than nine out of 10 Kosovans are ethnically Albanian and the ties between those countries are profound.

Was it a deliberate slight to pit Birmancevic against players who, bar the injured Tuci, were available for selection in his stead and presumably hold deep political differences with his home country? It is more likely to have been thoughtless idiocy: such flags are not new sights among elements of Sparta’s support. But rumours of internal tensions, that had been simmering without obvious foundation for some time, grew louder when Rrahmani appeared to respond directly to the images. On Sunday he reposted an image on Instagram showing a banner that Kosovan fans had displayed at their recent match against Cyprus, showing their territory covered by an Albanian flag with the words: “Everyone’s dream, our reality.”

Rrahmani’s timing was unlikely to have been a coincidence. He was evidently speaking, however indirectly, to those asserting Serbian supremacy over his country and it is hardly an ideal battle for the ultras to have waded into given the £4.2m investment Sparta made in signing him from Rapid Bucharest two and a half months ago. It would not be a stretch to imagine the three teammates in similar shoes feeling similarly frustrated.

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There is no evidence of a falling out with Birmancevic, though, despite further media speculation this week. Figures in the players’ orbits are said to have rejected any idea of bad blood within the squad: Birmancevic and Laci, a midfielder who scored for Albania against Croatia at Euro 2024, are believed to be particularly close. The row surrounding Birmancevic can be interpreted as a sporting issue that has boiled over, through Saturday’s scenes in the stands, into another tale viewed through the magnifying glass of Balkan hostility that has no day-to-day bearing within Sparta’s setup.

Sparta were moved to release a statement on Sunday that demanded “unity and a professional attitude” from everyone representing the club. That was open to interpretation but the statement continued by reasserting that Birmancevic is injured and unavailable for selection. It asked for an “atmosphere of mutual support and cooperation” amid turbulent waters.

That will be expected to manifest itself in a heady environment on Wednesday, when Sparta and their under-pressure coach, Lars Friis, aim to show again that Czech football is on the rise. The hope will be that, in what should be such a progressive corner of the region’s sporting scene, actions that revive friction from another area’s traumatic history are consigned to the past.