A make-or-break threat to the financial future of Cardiff City kicked off at the High Court on Wednesday.
Swiss investment bank Langston is suing the club over £24million in loan notes and is seeking summary judgment for immediate repayment of the debt.
The Championship club, still savouring Sunday's FA Cup quarter-final victory against Middlesbrough, want repayment deferred and the case to go to full trial.
The Bluebirds face possible administration if Langston succeeds at the two-day hearing in London before Mr Justice Briggs.
Langston's counsel, Michael Driscoll QC, told the court it was common ground that Langston was a substantial creditor of the club and that the debt owed to it was in excess of £15million.
It was also common ground that Langston loaned £24million to the club in 2004, and it had yet to be repaid anything.
It was the club's case that nothing was payable at the moment.
Mr Driscoll said the question for the court was whether there was enough in what the club said to justify the case going to trial and not being dealt with summarily.
It was Langston's case that there was not, and that it was an appropriate case for summary judgment which was "clearly desirable" as it would avoid a great deal of cost and time spent in litigation and uncertainty.