UEFA are facing a major legal claim just months into the new season, with the Champions League thrown into chaos as a result.
European football's most prestigious competition is well underway, with Bayern Munich and Arsenal the early pace setters in this season's league phase.
This is only the second season using the 'Swiss model', which replaced the traditional group stage system.
Under the new format, clubs compete in a 36-team league table, playing eight matches against eight different opponents - four at home and four away.
The top eight teams qualify directly to the knockout stage, while the next 16 sides then compete in a playoff round.
The bottom eight are eliminated from the competition.
Supporters have credited the Swiss model for producing more high-profile fixtures throughout the campaign, such as Liverpool against Real Madrid, with the Reds winning 1-0 over the Spanish giants on matchday four.
Liverpool defeated Real Madrid in the Champions League on Tuesday. (Image: Getty) However, others argue it makes the tournament too long and reduces the jeopardy that was present in the old format.
Now, UEFA face an £18 million legal claim after being accused of stealing the concept behind the new Champions League format.
According to The Sun, a Chilean sports consultancy called MatchVision has launched legal action against European football's governing body, alleging that they first proposed the concept more than a decade ago.
MatchVision is led by Leandro Shara, who said he trademarked the concept in 2006.
The company claims it presented the proposal to UEFA in 2013 and showcased it at several sports conferences over the following years.
They also allege that similar competition formats have been adopted in several countries and that FIFA recognise the model as MatchVision's intellectual property.
UEFA president Aleksander Ceferin. (Image: Getty) Shara said: “I am the creator of the format.
“And FIFA has recognised its intellectual property rights and the algorithm that develops it.
“I am not seeking my fortune.
“Only that my rights, investment, knowledge of the format be recognised.
“And that I reap what I have sown and watered.”
UEFA reportedly has 20 business days to respond to the claim.
A UEFA spokesperson told SPORTbible: "UEFA will defend its position."
The Athletic reported that MatchVision started legal proceedings in April, when it filed documents in Spain.
The case was initially assigned to a commercial court in Madrid; then, in September, it was transferred to a court in Lausanne, Switzerland, where UEFA are based.
It remains to be seen whether MatchVision will be successful with its legal action.
But the case threatens to cast a shadow over the Champions League just two seasons into its new era.