City were leading 1-0 at half-time courtesy of Mario Balotelli but ran the Red Devils ragged after Jonny Evans' red card two minutes after the restart. Balotelli scored a second, substitute Edin Dzeko scored twice and David Silva and Sergio Aguero also netted, with Darren Fletcher with the home side's consolation. Ferguson pulled no punches in his post-match assessment of a result that puts City five points clear of their rivals at the top of the Premier League table. "It was our worst ever day," said Ferguson. "It's the worst result in my history, ever. Even as a player I don't think I ever lost 6-1. That's challenge for me too. "I can't believe the scoreline. The first goal was a blow for sure but it was retrievable at 1-0. "The sending off was a killer for us. We kept attacking when we went 4-1 down and we should have just said: 'We've had our day."' Ferguson was particularly frustrated with some of his senior players for allowing United to continue playing open football with a man down. "We just kept attacking. They were attacking three versus two. It was crazy football," he said. "I thought with the experience we've got - Rio Ferdinand, Patrice Evra - they would (defend more) but we just kept attacking. Sometimes there has to be common sense about it. It was a bad day." The Scot attempted to find some positives amid his darkest hour and suggested his side would be sufficiently chastened by their embarrassing loss to produce a big response. "We'll come back. By January we'll be okay. We usually get the show on the road in the second half of the season and that will have to be the case," he added. "We've played all the teams around us and they have all to play each other so the second half of the season is important to us now. "We will react, no question about that. It's a perfect result for us to react to because there is a lot of embarrassment in the dressing room and that will make an impact." The scale of the defeat did concern Ferguson, though, as he looked ahead to the potential importance of goal difference as the season progresses. "What did concern me was the goals for and against. Goal difference may count. Last year it was in our favour, most years it is in our favour...this time maybe not." Micah Richards believes City are ready to throw their 'noisy neighbours' nickname back in United's face after the stunning win. Richards, who put in a tireless performance at right-back, was quick to remember Ferguson's famous quip about City after the match. "People call us the noisy neighbours but here we are. We have a good set of lads and we want to show people what we can do. "I think we did that today. It's what dreams are made of. We all know how good United are and how good they are at home. But they know about our attacking force - Balotelli, Dzeko, Aguero, Silva. "To come to Old Trafford and win gives confidence, especially the way we won. We'll only go forward now." Richards conceded that he had not expected the game to be quite so one-sided and admitted Evans' dismissal was key. "I'm still gobsmacked to be honest. To come here and win 6-1 in unbelievable," he said. "They had 10 men so you have to let them off a bit but in the first half we defended well and took the chance when it came." City boss Roberto Mancini chose to focus on the three points rather than the emphatic scoreline. The club's fans will no doubt delight in holding bragging rights over United after such a decisive scoreline - but Mancini insists the size of the victory was not the important factor. "It's not important 6-1. It's important that we beat a fantastic team. That is important," the Italian manager told Sky Sports News. "It is important for our confidence because I don't think it's easy to come here. "When you come here to play at Old Trafford it is an honour, because United are a strong team and you can have some problems." Evans' sending off at the beginning of the second half triggered a downward spiral for the hosts and Mancini admits things ran more smoothly for his side after the dismissal. But the manager hailed the home side for continuing to attack even when reduced to 10 men, with their efforts paying off when Fletcher notched a consolation strike late on. "After the sending off it was easier but we were playing very well. The first 25 minutes United played well but they didn't have more chances," he said. "I have more respect now for United because after the sending off they continued to try and score. I think that's an incredible mentality. "If we want to arrive on the top like them we should improve in this mentality." Mancini was pleased with the display of Balotelli, who shrugged off more controversy in his personal life to score two goals, having reportedly set fire to his mansion this weekend after allegedly letting off fireworks in his bathroom. The manager added: "I'm happy for him because he scored another two important goals and he played well. He was serious on the pitch."
