The final phase of the 2025–26 Serie A season has descended into chaos following the decision by Rome authorities to postpone the derby between AS Roma and SS Lazio to Monday, May 18. This decision has incited a contentious institutional dispute with the Lega Serie A and has the potential to significantly alter the penultimate matchday of the season, which is a critical fixture in the Champions League race. The rivalry between the two capital teams has a long history of fan violence, which is why the Italian Ministry of the Interior had already ordered that the match not be played in the evenings over the weekend. On Tuesday, the Prefecture of Rome—the government body that coordinates security and public order in Italy—officially announced the postponement to Monday evening at 8:45 PM, citing concerns about the simultaneous presence of the Internazionali BNL d'Italia, the major international tennis tournament taking place at the Foro Italico, just a few hundred meters from the Stadio Olimpico. In the statement, the Prefecture explained that the decision was made "in light of the assessments carried out by the Provincial Committee for Public Order and Safety", with special attention to "issues related to the management of public order and urban mobility" during a globally significant event like the Rome tournament. The Lega Serie A, on the other hand, reacted quickly to the decision, claiming that the postponement violated league rules. In Italy, teams competing for the same objective—European qualifying or relegation survival—must play simultaneously in the final two matchdays to prevent gaining an advantage. The League had previously scheduled Roma-Lazio, as well as the other crucial Champions League matches, for 12:30 on Sunday. Lega Serie A CEO Luigi De Siervo confirmed the league's position: "Is it already decided that the Rome derby will be played on Monday? I don't think so", he told AGI. "A formal, reasoned statement will arrive, carefully considered. Simultaneity will necessarily be guaranteed". The League's position is clear: if the derby is postponed to Monday, the other key Champions League matches must also be moved to the same time. Another issue complicates the situation: the USB union has called for a national general strike on Monday, May 18, affecting public transportation, schools, and the public administration. In Rome, the ATAC transportation operator has already warned of serious disruptions to the metro, buses, and trams, which will have a considerable impact on fan flow at the Stadio Olimpico. During negotiations about possible organizational alternatives, De Siervo reportedly suggested postponing the Internazionali d'Italia final, which was instantly rejected by the president of the Italian Tennis Federation, Angelo Binaghi.