As well as local bragging rights being at stake, Premier League champions Manchester City and League Cup holders Manchester United know the winner of a first major cup final between the two will be celebrating a rare double.
City also have the dream of a Treble, knowing victory against their neighbours would leave them just needing to beat Inter Milan in next Saturday's Champions League final to match a feat achieved by only one other club in English football.
And that team to win a Premier League, FA Cup and European Cup in one season? Yep, Manchester United - and the desire to keep their historic achievement in 1999 to themselves is obvious.
It all makes for some cup final.
Pep Guardiola's men are now just two games away from becoming the 10th European side to sweep the board - and it certainly hasn't gone unnoticed among the red half of Manchester.
Even before United's semi-final win against Brighton, former goalkeeper Peter Schmeichel - a key member of that 1999 squad - joked: "That is why it is so important that we now beat Brighton, so we can stop them."
Another member of that side, Gary Neville, told Sky Sports as cited by Sports Central: "Man Utd want the opportunity to take away the Treble.
The question about the importance of 'stopping the Treble' was posed to manager Erik ten Hag several times in the immediate aftermath of their semi-final win.
The Dutchman said: "We will give everything and, when I say everything, it's everything… the fans can rely on that. "We want to give that against City. We want to go and give the fans that."
For the United fans, you get the feeling that stopping City is almost as important as their own cup double - having already won the Carabao Cup - with songs often sung around Old Trafford about their proud boast of being England's only Treble winners,
United have been in this position before.
In 1977, they faced a Liverpool side who had won the league and had a European Cup final to follow four days after the FA Cup final. United won 2-1 at Wembley to end Liverpool's Treble hopes. They did go on to beat Borussia Monchengladbach 3-1 in Rome.
Liverpool fans will be quick to remind of their two trebles - the European Cup, League Cup and First Division title in 1984 and FA Cup, League Cup and Uefa Cup triumphs in 2001. In 2019 City became the only English men's team to win a domestic treble of league, FA Cup and League Cup.
But, with just four trebles of various make-ups in the history of English men's football, City know they are on the verge of true greatness.