After last weekend's draw with Liverpool, and of course Tuesday night's Champions League disappointment, it won't be easy for Arsene Wenger to pick his players up, mentally as much as physically, as Arsenal will have been devastated.
But this is when people like Wenger really do earn their money by saying the right things to lift his players and trying to coax another big performance out of them. And I think the players themselves won't need an awful lot of motivating for the game with Manchester United.
Sure, 24-48 hours after getting knocked out of the Champions League in the manner that they were, the feeling of depression and disappointment would have still been there, but then you get to Friday and you start to turn your mind to the weekend and what might be - and what still could be.
Let's not forget, Arsenal have plenty of good players and good players cope with disappointments and are able to lift themselves. Physically, we don't know how much the season has taken out of them so far. Arsene Wenger hasn't been able to leave players out now and again to recharge the batteries because of the injuries that he has had - to the likes of Eduardo, Robin van Persie, Tomas Rosicky and Bacary Sagna - and the size of his squad. That hasn't helped in many respects but we won't know how much of a toll that has taken on the players until the whistle goes on Sunday afternoon and Arsenal start to play. They may feel mentally that they're up for it and ready to go but they may find that the engine is running on empty. We don't know, but what we do know is that Wenger will be making all the right noises but I think, despite what he has been saying, he thinks it is a big ask. But why not ask his players for one more performance? They have five games left of their season, they know what is required - they have to win them all - so why not?
Luxury
Sir Alex Ferguson had the luxury of being able to rest Wayne Rooney and Cristiano Ronaldo in midweek, but I'm not so sure they will have needed that rest, they would rather have been playing, believe me.
Ronaldo hardly gets a rest, but he is only 23 and is hardly needing a breather, and Rooney is even younger so it wasn't like they desperately needed it. And they would be fresh at this stage anyway because they are playing well and mentally everything is going for United at the moment.
But Ferguson took the opportunity, in a game that he felt was won, to leave two of his stars out and Wenger hasn't been able to do that with Fabregas for example.
Manchester United have injury problems of their own and the loss of Nemanja Vidic is a big one, but I think Rio Ferdinand will play.
If he comes back on after being stitched up after playing for 45 minutes against Roma then I don't see any reason why four days later, with the wound stitched up properly and padded properly, he shouldn't be able to play in a game as crucial as this.
I think if Vidic was fit then Rio may well have been rested but with Vidic out, they will do all they can to get Ferdinand out there, as without Vidic it is vital that they have him at the back. You wouldn't want to go into this one without your first choice centre backs and having to put out a pair that may not have played that often together would be far from ideal.
Run-in
Of the three teams Manchester United have the toughest run-in. After Sunday's match they have Blackburn away, and then Chelsea away.
So United are going into three games where conceivably they could drop points. Chelsea have an easier run-in with Wigan at Stamford Bridge on Monday night, then Everton, another team that are maybe running a bit on empty, at Goodison Park where they always do quite well, so they will fancy their chances there.
The next three games will certainly define Manchester United's season and if they come out of them unscathed then we might as well wrap up the title and give it to them there and then. But at the moment the Premier League title is still very much up for grabs; I don't think anyone would argue with that. Some may say that Arsenal have gone, they're shot and are out of it, but I think with only six points between them and United - and it could be just three points after this match - you cannot discount Arsenal.
If Wenger's team get beat on Sunday, that's it, done and dusted. And as long as Chelsea win on Monday against Wigan, which they probably should do, then we have a two-horse race. An Arsenal win would open it right up and would mean that three teams have the distinct possibility of winning the title and you would be hard pushed to bet on one.
I actually wanted to write before this week's matches, but when I read this piece by Andy Gray, I thought I could not have put it better.