Sir Alex Ferguson is so concerned about Manchester United's sudden slump in form that he has been forced to gamble with the fixture list, on a day that Jamie Carragher warned the faltering English, European and world champions that Liverpool had replaced them as the country's in-form team.

United's lead at the top of the Premier League has been cut from seven points to one and Ferguson has seen his side lose their last two games, with three players sent off in the process. The manager is now so alarmed that he has decided to prioritise their first Premier League fixture after the international break, at home to Aston Villa, by allowing it to be played at 4pm on Sunday 5 April, even though that means his players will have only two days to prepare for the home leg of their Champions League quarter-final against Porto.

Sky had offered to bring forward the Villa game to 12.45pm the previous day so United would not have to play two crucial games in the space of barely 50 hours, exactly the kind of gruelling schedule that Ferguson would usually be desperate to avoid. ­However, the Scot has drastically altered his thinking in the wake of United's 2-0 defeat at Fulham on Saturday and the 4-1 humiliation against Liverpool a week earlier.

When the match was originally chosen for live television United announced it would automatically revert to a Saturday kick-off if they were drawn to play in the Champions League on 7 April. Instead, the club confirmed today that "contrary to previous advertising" they had changed their mind. Ferguson publicly declared last month that the Champions League was his "priority" but he has now decided it is more important that those United players who will be away on international duty over the next week and a half have an extra day to prepare for the visit of Martin O'Neill's side.

Just to add more pressure on Ferguson, the Liverpool vice-captain, Carragher, used Sunday's comprehensive victory over Villa to send out a warning that his side are now the form team in the Premier League. "United will know that we are in there," Carragher said. "United will ­realise they are in a fight for the league. At the moment we're probably the form team in the league, and this is the best time of the season to be in form."

Carragher believes Liverpool's 5-0 thrashing of Villa, following on from scoring four goals in each of their games against United and Real Madrid, demonstrates that Rafael Benítez's side can catch and overhaul their fiercest rivals.

"To score five goals against Villa was a magnificent achievement," he said. "That will have sent a message out to United and Chelsea. Let's not kid ourselves; they'd have been watching the game."

Carragher added: "We are maturing and getting used to the demands of fighting for a title. We were there earlier in the season but, having not been in that position before, maybe we didn't know how to deal with it. We've probably found it difficult a few times this season to cope with that, so to run out 5-0 winners was a great result. It was important we capitalised [on United losing at Fulham]. We're well aware that the title is in Manchester United's hands, but we're trying to put them under as much pressure as possible."

Villa are in the midst of a slump and have a miserable record against United, with 13 successive defeats at Old Trafford and no win there since 1983. However, Ferguson has had to take into account that Wayne Rooney and Paul Scholes, both of whom were sent off against Fulham, and Nemanja Vidic, dismissed against Liverpool, will be suspended, while Dimitar Berbatov could also be ruled out by an ankle injury. Carlos Tevez is part of the Argentina squad preparing for World Cup qualifiers against Venezuela and Bolivia, while Anderson is getting ready for Brazil's games against Ecuador and Peru, and Ferguson believes neither player would be in a fit condition to play the next morning.

Nonetheless, it represents a significant gamble given that Porto are currently seeking permission to move forward their league match against Vitoria Guimaraes on 5 April by one or two days.

Ferguson's decision has been taken with a certain amount of reluctance, aware that he is risking giving Porto a considerable advantage, but he is said to think of it as the lesser of two evils. Liverpool will move to the top of the table, albeit having played two more games, if they win or draw at Fulham on Saturday week, and Ferguson knows there will be a tense atmosphere at Old Trafford the following afternoon.