Manchester United fans have warned the club that they risk "outright rebellion" if they introduce further ticket price rises.
Supporters have also told co-owner Sir Jim Ratcliffe that doing anything to worsen the mood among United's fan base would affect the matchday atmosphere at Old Trafford which could send team performances into "catastrophic tailspin."
Ratcliffe has already been heavily criticised by fans for the mid-season decision to raise ticket prices to £66 ($82.5). And in an open letter to the 72-year-old British billionaire, supporter group M.U.S.T have issued a warning about the impact of further increases.
"As you consider forthcoming decisions on match ticketing policies and pricing, we urge you to pause and carefully reflect on the timing, potential consequences, and long-term impact of any major changes," M.U.S.T. said in a letter to Ratcliffe.
"A price increase or significant ticketing policy changes would land very badly with fans at this time. Negative sentiment comes with financial costs, as discontent escalates into active protests and disillusionment.
"This discontent could lead to outright rebellion, with consequences not just for matchday revenues but also for sponsor relations and the club's global brand."
M.U.S.T have warned that provoking further anger among fans could lead to more poor performances in home games.
Head coach Ruben Amorim has already suggested the team are struggling to play at home because of anxiety inside the stadium. United have lost four of their last six home games but were able to secure positive results at Liverpool and Arsenal earlier this month.
"Fan dissatisfaction affects the matchday atmosphere, creating performance anxiety for players, rather than the vocal support needed to inspire them," continued M.U.S.T.
"A passive or even hostile atmosphere at Old Trafford compounding struggling team performances could spiral into a catastrophic tailspin."