Manchester United are preparing to battle Arsenal over the number of away tickets made available for next month's FA Cup clash at the Emirates Stadium. United have reportedly contacted the FA after the Gunners failed to offer a full allocation for the blockbuster third-round clash on January 12.
The two most successful teams in FA Cup history - boasting 27 titles combined - have been pitted together at the first hurdle.
United won't have considered many tests tougher at the start of their latest defence, having beaten Manchester City to earn a 13th crown in May.
According to competition rules, the Red Devils are entitled to 15 per cent of the Emirates Stadium's 60,000 capacity for the mouthwatering clash.
The prospect of around 9,000 supporters making the trip down from Manchester was enough to soften the blow of a daunting draw.
However, Mail Sport report that Arsenal have provided United with a significantly lower number of tickets, believed to be less than 8,000.
It's claimed that the decision won't go uncontested, with the two Premier League heavyweights already holding discussions.
United are said to consider the underwhelming allocation unacceptable and have now raised the matter with the FA to find a favourable solution.
The report adds that Arsenal made the decision with the safety of fans in mind, cooperating with local police and the safety advisory group.
However, United allegedly refused the reasoning, insisting that the stadium's size and modern design could handle a sizable away end.
The M16 giants have reportedly also pointed out that kick-off has already been brought forward to 3pm to counter crowd problems.
United are thought to have escalated their case to the authorities because they understand they have a responsibility to fight for their fans' rights.
Arsenal beat Ruben Amorim's side 2-0 at the Emirates in their Premier League meeting at the start of the month, scoring twice from corners through Jurrien Timber and William Saliba.
Amorim will be hungry for vengeance in the cup tie, and he knows exactly what his players must improve to get a result on their return to the capital.
"Set pieces. That is important," the Portuguese head coach responded to Amazon Prime Sport when asked what must improve from the Premier League defeat on United's return to north London.
"And we have to be more aggressive near the opponent's box. But we have a lot to improve in all areas of the team."