Ferguson:
"When two teams with this ability meet it can go either way and maybe Sunday will be our time. On one or two occasions they have had a bit of luck and maybe we will get some now.
"We have the opportunity to go six points clear but it may galvanise Chelsea. They may think they can't lose and it might not do them any harm. But we're at home and that is important. I hope the atmosphere is electric and feel we have a massive chance.
"They'll play the way they always play, setting out to make sure they're strong defensively and hoping they can take advantage of their attacking situations.
"Being behind us and wanting to change that situation may also galvanise them. But it is always a big occasion when two teams close together at the top of the table meet. We see it as a fantastic opportunity, especially as they were a long way ahead of us when we met at Old Trafford last season. Most seasons, when you are in this sort of race, you try to do your own job and then hope that some other team will do you a favour by beating your rival. But this time, we have the opportunity to do that ourselves.
"When you lose a game like that [Celtic], you sometimes have to go into the dressing room and address some issues as to how you lost the game.
"We didn't have to do that on Tuesday because the team played exceptionally well. What they did, they started enjoying the game and forgot the competitive part of it. They started to enjoy it, relaxed, controlled the game and lost it. I don't know what you can say to footballers in that situation because I couldn't point at one player who didn't play well or play his part."
About the ref, Howard Webb:
"He is a young referee and we should let him get on with the game and give him a chance.
"As long as he is fair, no-one can complain. I certainly hope it is not a game where we see players start to crowd round the referee as has happened so often recently."
Giggs:
"We'll definitely be looking for a win. It would be a psychological blow to them to go six points behind and find themselves chasing us for once, instead of the other way round. And although nothing will be decided by this one game, victory would also be a huge boost to us. We need a good result after our Champions League defeat in midweek. We'd also love to put one over Chelsea after losing 3-0 at Stamford Bridge seven months ago and then having to watch them celebrate retaining the title.
"We had to put up with Arsenal's celebrations after they clinched the title at Old Trafford four years ago, too. You remember things like that and hope they don't happen again.
"We have proved over the last couple of seasons we are as good as them but Chelsea have just been far more consistent. Their dominance has been hard to take because we have become used to winning and challenging for league championships. But at least this year we have managed to get off to a good start. For us to carry on progressing, we need to be competing in games like Sunday's and making sure we get the right result."
About Saha:
"Louis has been fine. People miss penalties all the time. It is one of those things. Louis has had a brilliant start to the season. He is still full of confidence and I am sure he will be flying on Sunday."
Rooney:
Chelsea like sitting back, trying to nick a 1-0 win.
"At United we go out to attack, running at teams with pace.
"I'd rather play 100 times on the attack than one defensive game.
"Winning would give us belief that we can go on and win the Premiership.
"In terms of points it won't make that much difference but a victory would be a stepping stone. These are the games you have to win to take the Premiership so we have to do well in these matches. If we can do that then we'll leave ourselves in a good position for the end of the season.
"We have shown we can lift ourselves for the big matches so we'll be looking to do that again. The Chelsea game will be very important for us, especially in terms of keeping our noses in front.
"But it's not a two-horse race just yet because there are still a lot of games to go. We have seen before how things can change quickly.
"I think in my first season here we were ahead of Arsenal for second place but then they came from nowhere to go above us.
"Anything can happen in football - just a couple of results can turn a season around. We're aware of that and that's why we want to keep winning and not allow teams such as Arsenal or Liverpool to get back into it.
"That's why we are going to need the experience of Paul Scholes, Gary Neville, Ryan Giggs and Ole Solskjaer in the season half of the season."
Neville:
"Our performance levels are better than at any time in the first six months of last season.
"We've blown teams off the park with quick attacking play, two wide players, two centre-forwards, and we've blitzed them in 20-30 minute periods."
Ronaldo:
"I didn't do an interview and I didn't say the things I have seen written. [alleged critcism of Chelsea's play]
"I respect Chelsea and everybody in their team. But I have my own ambitions for my own team and I hope to win on Sunday.
"I am enjoying myself a great deal.
"The team are playing well, which helps. I feel I am learning and improving every year.
"I am becoming more mature and more consistent. I understand what it means to play for Manchester United a lot more. I feel great and I want to keep it going."
Claude Makelele stokes it up:
"Victory at Old Trafford would be sensational for silencing the many mouths at Manchester United which have been talking too much about being leaders.
"In recent years, I have noticed some fear in United when they have played against us.
"Their anxiety about winning has negative consequences for them because it turns into nerves and that is dangerous for a team. It's true United are at a higher level than last season but I would always put my money on Chelsea as the favourites.
"In this match we need to demonstrate we are the kings of the Premiership."
Joe Cole:
"Giggs and Ronaldo are world-class players and will give our back a tough day, that's for sure. But if we play the diamond [midfield formation] we should control that area and have more possession, and on a big pitch like Old Trafford if you keep the ball well, that's half the battle. There's no nervousness, and we won't be out-muscled. We're a powerful side, physically and mentally.
"We've been very impressed with them, but we're more than capable of winning the game. They say they're the best side, we say we are. Come 6 o'clock, we'll see who is. If we play at our top level, we'll win.
"This is every bit as big as when we played Barcelona in the Champions League, maybe even bigger, because we have to meet the United guys when we join up with England, and we don't want to go there having lost. It's not a nice experience.
"Only time will tell. We've got to win the league. The best team always wins the league. We're chasing because we're three points behind, whereas in the last two seasons we've run away with the league and had it sewn up really early. It's good that United have set us a new challenge. We are looking forward to clawing it back. There's no apprehension, everyone is really excited.
"I don't think the pressure is any different chasing or being chased, either way you have to win. In the last two seasons we've trailed off in April and May because we've had the league won. This time I'm hoping it will go all the way and it will be more exciting.
"United will not have enjoyed watching us win the league for the last two years. That will have hurt them. I'm not too interested in the psychological side of it, but I know that if we win, the lads are going to be on a high for the next three or four weeks."
Marcel Desailly, the former Chelsea captain:
"Football goes in cycles and I just don't think Chelsea can be as dominant as they were in the last two season. This is going to be Manchester United's season.
"For me, Paul Scholes is at the base of everything that's good about Manchester United. He's the one who is going to distribute the passes, the one who will direct the game. He has the vision and the reading of the game and he can play short with Wayne Rooney or long out to the flanks.
"One of United's big pluses is the ability of both Scholes and Rooney to drift between the lines: it makes them very hard to pick up and it leaves defenders and midfielders who are supposed to be tracking them in two minds.
"Because United are at home, they will not change their way of playing - they're going to have that attacking line-up that has looked so good at times this season. You have five really attack-minded players with Ryan Giggs and Cristiano Ronaldo out wide, Louis Saha running through the middle, Rooney dropping off into spaces and Scholes pulling the strings behind them and also coming late into the box."
Fat Frank:
"I think these big games are the ones when you need your big players to stand up and be counted.
"Big players thrive on these games and I'm sure those two will. They are world-renowned top players because they perform in big games as well.
"They had almost a decade of dominance - along with Arsenal to an extent - so three years for us would be great though there's probably a longer period of time we would have to reach to be able to say we have done what they've done."
BBC match preview:
Manchester United have no new injury worries ahead of the top-of-the-table clash with champions Chelsea.
Rio Ferdinand had been a doubt after picking up a foot injury but has been passed fit, while Patrice Evra could come in for left-back Gabriel Heinze.
Chelsea should have top scorer Didier Drogba (ankle) and midfielder Michael Ballack available after slight knocks.
Frank Lampard returns to the squad and Ricardo Carvalho (ankle) has recovered, but Salomon Kalou is still sidelined.
Man Utd (from): Van der Sar, Kuszczak, Neville, O'Shea, Brown, Ferdinand, Vidic, Silvestre, Heinze, Evra, Ronaldo, Fletcher, Scholes, Carrick, Giggs, Richardson, Rooney, Saha, Smith.
Chelsea (from): Cudicini, Hilario, Ferreira, Geremi, Terry, Carvalho, Boulahrouz, Bridge, A Cole, Lampard, Essien, Ballack, Makelele, Drogba, Robben, Shevchenko, Wright-Phillips, J Cole, Diarra, Mikel.
BBC Weather:
10°C and sunny at 4pm.