Sir Alex Ferguson believes Premier League basement dwellers Portsmouth are in a false position.

Ferguson's Manchester United side visit Fratton Park tomorrow looking to collect another three points and exert some pressure on Chelsea ahead of their eagerly-anticipated London derby with Arsenal on Sunday.

Even with Avram Grant installed as manager, few expect anything other than an away win, with Portsmouth believed by many to be certainties for the drop given their much-publicised financial strife and the loss of so many influential players since their 2008 FA Cup win under Harry Redknapp.

But Ferguson is not so sure.

After analysing Pompey's recent performances, he feels Grant can look forward to better times.

"Portsmouth have some very good players," said Ferguson.

"I have looked at their videos and they may be in a false position.

"But being bottom of the league does create a reaction from owners and management of a club."

That reaction resulted in this week's dismissal of Paul Hart.

Most football followers will have a great deal of sympathy for Hart given the constraints he has been working under.

Yet last week's defeat at Stoke, which left the south coast outfit adrift at the foot of the table, triggered a change at the top, with chief executive Peter Storrie admitting he had no option in creating further upheaval at a club that has been mired in financial woes and ownership controversies.

"It doesn't matter which club it is, when you have a change of ownership there will be a certain amount of disruption," said Ferguson.

"You get new policies coming in, or there might be a new financial outlook. You can see how it can have an effect on the pitch.

"And owners of a club don't like to see their team at the bottom of the league. That is the danger position.

"If you are third or fourth bottom you think everything will be OK. But when you see your team going bottom it creates a dread about where they are going to be next season."

There is an irony about Grant being in charge against United tomorrow.

When he succeeded Jose Mourinho at Chelsea his first match was against the Red Devils - he lost - as was his last, the 2008 Champions League final when the Blues were defeated in the Moscow rain after John Terry had missed a penalty that would have given his side victory.

Grant has kept in touch with Ferguson since and, after tomorrow at least, he will have plenty of good wishes from Old Trafford for the fight that lies ahead.

"Avram is a football man and there is no doubt he will be glad to get back into the game," said the United chief.

"He has a task on his hands because his team are bottom of the league. But hopefully he can manage it."

Ferguson will recall all his big guns following Wednesday night's Champions League defeat to Besiktas, with Wayne Rooney, Edwin van der Sar, Ryan Giggs and Paul Scholes among those who missed out as United surrendered their 23-match unbeaten home record in the competition.

However, he will be forced to watch from the stands as he starts a two-match touchline ban imposed following his verbal attack on referee Alan Wiley.

It is an inconvenience United's players could have done without, although Darren Fletcher is not convinced it will have any major effect.

"Obviously the manager is a massive presence on the sidelines but we have plenty of experience in (coaches) Mick Phelan and Rene Meulensteen and I am sure he will be in constant contact with them," said the Scotland midfielder.

"In an ideal world we would have him there but unfortunately that is not the case.

"We cannot let that affect us. We just have to focus on getting the result."