Sir Alex Ferguson has talked up the magnitude of Monday's Manchester derby, expressing his belief that the side that eventually misses out on the Premier League title will be haunted by regret.
United and City face one another at the Etihad Stadium next week, and the outcome is likely to be key in deciding where the Premier League title is heading with just three matches of the season left to play.
The table-topping Red Devils have a three-point lead at the summit and will likely feel avoiding defeat should be enough to retain their title, but Ferguson is taking nothing for granted ahead of a vital game.
The Scot said: "This is the derby game of all derby games - whoever loses will be tinged with regret. It's in the blood of the supporters and I know lots of fans who would give everything to win this game.
"If one loses, they are going to be reflecting on what may have been. But then you look at the points totals that both teams are probably going to amass and you'll see that it's championship form.
"It means everything to the supporters. Going in to work next Tuesday morning will be the most important day of their lives, for both sets of fans."