By Gary Pallister BBC pundit and ex-Man Utd defender

This Sunday's game between Manchester United and Chelsea was always going to be different as both sides have failed to hit top form so far this season.

But the departure of Jose Mourinho this week has obviously given the Old Trafford meeting a whole new twist.

It will be interesting to see how Chelsea's players react to his exit.

Mourinho (left) and Ferguson had their battles - on and off the field

Didier Drogba apparently wants to quit while it could have an impact on whether Frank Lampard commits to a new contract or not.

Mourinho had such a close relationship with his players - he heaped all the praise on his side and really looked after them.

It will be a case of wait and see what happens with the new manager Avram Grant and the way the players take to him.

Certainly at the outset he is not going to have the same relationship as Mourinho had - it will take time to build up the trust with the players.

When a new guy comes in, as a player you wonder if he will rate you or see you as part of the future.

Things like that weigh on players' minds but ultimately they will want to impress.

Grant has been at the club for a few months so the players will have some idea of who he is and what he is about, but it is very different being in the background as a coach and being the main man.

It can affect players' mentality as they are not 100% where they will stand with the new guy.

What the players will miss is Mourinho's character and personality - it was a big part of why they wanted to play for him.

That relationship is now gone.

One person who will not be distracted by this week's events is Manchester United boss Sir Alex Ferguson.

He will be more worried about what he is doing with his own team.

United got a good result in midweek but again struggled in the first half.

They have not hit their top form and he will be more worried about fitting all these wonderfully talented attacking players into a system that will make them as successful as last year.

Sir Alex will be expecting Chelsea to be just as strong this season.

The Blues have had the better of Manchester United in recent head-to-head meetings.

606: DEBATE How will Chelsea's players cope with the loss of Mourinho?

But a lot of teams have struggled against Chelsea because they have the financial clout that United once took for granted.

Whoever manages Chelsea can consider themselves a very fortunate man because they have the richest owner in the footballing world.

If Avram Grant does not work as manager they will get another big name - they will not sit still.

The animal that is Chelsea is not going to go away - as long as Roman Abramovich is there they will be one of the big hitters.

Football throws up some strange results, but United will be firm favourites for Sunday because of the turmoil that has gone on at Stamford Bridge.

The players will be on a downer because they have lost a friend as well as a manager.

They are already without Drogba and Lampard so it makes things even more difficult for them.

It is going to be a huge job for them to pick themselves up in such a short space of time and then play one of your title rivals on their own patch.