Fergie: I've been getting it all wrong

Eleven points behind Arsenal ahead of Sunday's meeting with their great rivals at Old Trafford, time is not on Ferguson's side. Yesterday he at last signalled it was time to stop experimenting.

'I also gambled a little with Roy Keane on Saturday and maybe that didn't work either,' added Ferguson. 'Maybe he wasn't 100 per cent fit and maybe he shouldn't have played.'

It is not just the latest chapter in his assault on Europe against Sparta Prague here tonight that is preoccupying Ferguson. The shootout with Arsenal is very much on his mind.

He said: 'It's a massive game on Sunday and the gap between them and us in the League is a concern. It's not win-or-bust for us but it's very, very important.

'A win over Arsenal could really turn the whole season on its head. Somewhere down the line somebody has got to stop them, and it might as well be us.'

Admitting his own mistakes does not come easily to Ferguson. Part of the Scot's make-up has always been to convince himself that everything he does will bear fruit eventually.

Now that it has not, it is time to change policy and it is clear where the heart of his dilemma lies.

Asked yesterday if he knew his best team, the answer betrayed the fact that although his back four now pick themselves, and he will always be happy to rotate partners for Ruud van Nistelrooy, he is still troubled by his midfield.

Roy Keane - an absentee here tonight - will continue to play more often than not, while Paul Scholes continues to command his manager's loyalty.

Those two stalwarts apart, however, Ferguson would appear to be struggling.

'I think I'm nearer to knowing my best team,' he said. 'I certainly have nine or ten of them in my mind. 'I think my back four are settled now. I think with Gary Neville, Rio Ferdinand, Mikael Silvestre and Gabriel Heinze I have a defence who are formidable and powerful.

'In attack, I think there will be different types of games that require different strikers and there are partnerships that will suit some situations and not others.

'But in the centre of midfield it isn't as clear. I have to try to balance who can play with Scholes and Keane, because those two aren't always going to be able to play together.

'They're certainly our best two in that position, as they have the experience and the stature. But the other slots in there are up for grabs.'

To hear Ferguson trumpet the qualities of his back four will hearten fans. So far this season, the United manager has fielded more than 10 different defensive line-ups in all competitions and that confusion almost certainly contributed to goalkeeper Tim Howard's indifferent early-season form.

In the centre of the field, however, there are fewer reasons to be cheerful. Ferguson has spent a lot of money trying to reinforce that area and it is disconcerting to hear him admit that nobody has emerged yet to threaten Keane and Scholes.

Neither of 2003's summer signings, Kleberson and Eric Djemba-Djemba, has managed to take his opportunities thus far, while the progress of Darren Fletcher and John O'Shea would appear to have stalled. At the same time, Phil Neville must wonder how a summer pay rise and contract extension is supposed to tally up with one Premiership start all season.

Tonight, he may get his chance as Ferguson looks for a midfield anchor to protect the returning Scholes. In the long run, however, Ferguson's preferred choice remains unclear.

United arrived in Prague yesterday without captain Keane - who has flu - and without defender Ferdinand, who is attending the funeral of his grandmother.

There was also a scare when Argentina's Heinze limped out of training last night after an accidental clash with Van Nistelrooy, but both are expected to be fit.