The case involves a contractual dispute between a professional football club (Appellant) and player Kristian Fardal Opseth, along with Adelaide United FC (Respondents), adjudicated by the Court of Arbitration for Sport (CAS). The dispute arose from an employment contract signed in January 2019, which the player terminated unilaterally in June 2019 due to the club's failure to meet financial obligations, including delayed payments. The player issued default notices before terminating the contract and subsequently signed with Adelaide United FC. The dispute was initially brought before FIFA's Dispute Resolution Chamber (DRC), which ruled in favor of the player, ordering the club to pay compensation of EUR 580,000 plus interest. The club appealed to CAS, but the appeal was dismissed due to the club's failure to file the statement of appeal within the required 21-day deadline. The CAS panel emphasized that the time limit begins from the receipt of the decision, not the actual knowledge of its content, and strict adherence to procedural timelines is mandatory. The club argued that the deadline should be calculated from the receipt of a rectified decision issued on April 14, 2020, which amended the original March 30, 2020 ruling. The club also contended that the late-evening notification of the rectified decision was unreasonable, meaning the deadline should start the following day. However, the panel rejected these arguments, stating that the appeal filed on May 6, 2020, was still one day late, even if calculated from April 15. The Respondents maintained that the original decision's timeline applied, making the appeal 37 days late, and cited CAS precedent and Swiss Procedural Code provisions to argue that rectifications do not reset appeal deadlines. The panel bifurcated proceedings to first address admissibility, ultimately ruling the appeal inadmissible due to the missed deadline. The decision underscores the strict and automatic nature of procedural deadlines in CAS proceedings, with no exceptions for extensions or delays. The FIFA DRC's original decision remained in force, and the club's failure to comply with the payment obligations could result in sanctions, including a ban on registering new players. The case highlights the procedural complexities of sports arbitration, including the impact of external factors like the Covid-19 pandemic on legal timelines, and reinforces the importance of strict adherence to deadlines in legal proceedings before the CAS.