Nick De Marco played his part after an independent arbitration panel decided to scrap the English Football League's (EFL) salary cap for Leagues One and Two.
De Marco, who is one of the QCs representing Mike Ashley in Newcastle United's dispute with the Premier League, acted for the Professional Footballers Association (PFA) alongside Ravi Mehta in its arbitral challenge to the EFL.
Third and fourth-tier clubs voted the caps through last summer but the PFA believed they were 'unlawful and unenforceable'.
An independent panel has now ruled that the EFL were in breach of the Professional Football Negotiating and Consultative Committee's (PFNCC) constitution in introducing the caps, which were set at £2.5million per club in League One and £1.5million per club in League Two.
Reacting to the decision, De Marco tweeted: 'Delighted to have successfully represented the PFA in this important case about football salary caps.'
While Sunderland supporters would love to earn promotion to the Championship this season, the decision could yet have huge ramifications for the Black Cats if Lee Johnson's side stay in League One - particularly if the club's prospective takeover goes through.
The PFA now hope to 'open constructive dialogue to agree reasonable and proportionate cost control measures' for the future.
Gordon Taylor, the PFA's chief executive, said: "We were disappointed that the EFL decided to introduce salary cap proposals, which were voted through without the proper consideration or consultation with the PFNCC.
"As a result, in August 2020, the PFA served a notice of arbitration on the EFL stating the introduction of the new rules were in breach of obligations under the constitution of the PFNCC. We are pleased the panel upheld the PFA's claim.”
A statement from the EFL added: 'At the time of the adoption of the salary cap rules, the EFL included a provision to ensure that any decision such as this would have the effect of reinstating the SCMP rules that were in operation during season 2019/20, which links player related expenditure to turnover.
'The EFL will now discuss the matter of financial controls and implications linked to this outcome at a series of meetings with its member clubs later this week.'
