Irish league side Crusaders today won High Court permission to challenge a government-funded £25 million upgrade to Northern Ireland's national football stadium.
A judge ruled the club has established an arguable case that the redevelopment of Windsor Park amounts to unlawful state aid for its rivals Linfield.
Mr Justice Treacy granted leave to seek a judicial review on that point and on an alleged lack of transparency around the proposed scheme.
But he stressed that his decision has no bearing on the ultimate outcome to the case.
The Windsor Park redevelopment is part of a plan that also includes the Ulster rugby ground at Ravenhill and the GAA's Casement Park.
A total of £110m has been set aside for the three building projects through the Department of Culture, Arts and Leisure.
Crusaders claimed the upgrade to the stadium owned by Linfield breaches European Union competition laws and constitutes government aid.
It argued the proposals would create extra revenue streams and give an unfair advantage to a club already in a financially dominant position.
Lawyers for the Department insisted no final commitment has been given to provide the £25m earmarked in the Stormont Executive's Programme for Government.
Although the process was said to be at an advanced stage, the court was told stadium funding depended on agreement on a range of sporting and social integration projects.
Counsel for the IFA backed the contention that the challenge was premature.
Alternatively, if proceedings were against a policy first unveiled in 2011 they are out of time, he argued.
But Mr Justice Treacy said: "It's in my view arguably clear that the government has made a decision in respect of a funding package to redevelop Windsor Park, build a new stadium at Casement Park and redevelop Ravenhill."
Granting leave on the state aid ground of challenge, he confirmed: "The court holds that the challenge is not defeated at this stage on grounds of prematurity or delay."
The judge also allowed a claim about a lack of transparency on the process to progress, but threw out a further allegation that it breached fair competition laws.
He stated: "I should emphasise that the grant of leave says nothing at all as to how the case will ultimately be resolved following the provision of and consideration of all relevant evidence.
"The grant of leave merely signifies the case is arguable or worthy of further consideration."
Outside the court Crusaders director Mark Langhammer gave a cautious welcome to the verdict.
He said: "Our aim in all of this has always been to get a balanced and competitive league.
"At this stage what this leave hearing decision secures is access to the information on which DCAL and others made their decision.
"We will not get ahead of ourselves, we will simply get the information first and discuss it with our members."