Rio Ferdinand kicked a female steward by mistake - he meant to kick a wall - and a mass scuffle between United players and Chelsea groundstaff broke out after Patrice Evra claimed he had been racially insulted during an argument while warming down after the game.
Evra has been charged with misconduct and has a personal hearing at the FA on October 2, while Chelsea have also been charged over remarks allegedly made by groundsman Sam Bethell - which the club deny.
But both Evra and Fletcher do not believe there will be any hangover from last season.
Evra said: "It will not affect anything. We have a new story with every game and we just know we need to win against Chelsea for the confidence of the team.
"It's the perfect game for us, the spirit is there and we have to show our quality.
"But I'm not saying that if we beat Chelsea then we have won the league, or if lose the game we have lost the league."
Darren Fletcher believes the importance of the match is so great that last season's encounters will have little impact.
He added: "I don't think anyone is going to be even more fired up because of the past.
"It's a massive game and if you are not up for this match then you shouldn't be playing. Everything that has happened in the past will be forgotten and it's about what you do on that day to get the right result."