Sir Alex Ferguson has admitted Manchester United must treat every game as "must-win" as they look to put pressure on Premier League leaders Chelsea.

United had fallen eight points adrift of Carlo Ancelotti's men prior to kick-off against Everton at Old Trafford on Saturday night. But Darren Fletcher's brilliant volley ended such fears and with Michael Carrick and Antonio Valencia also finding the net after half-time, the Red Devils were able to celebrate their biggest win since August.

"We have to look at all the games as must-win now," said Ferguson. "We need to get on a run and be somewhere near the top of the league by New Year's Day. Then, in the second half of the season we can have a real go and give ourselves a chance."

With their place in the Champions League knock-out phase secure already, Ferguson can make plenty of changes for Wednesday's encounter with Besiktas and keep his preferred team fresh for the long trip to Portsmouth on Saturday.

It is a fair bet Fletcher will be involved at Fratton Park after another fine performance. Over the last 12 months, Fletcher's reputation has soared.

Ferguson is obviously well aware of his fellow countryman's abilities at shutting down the opposition. But the United manager admitted Fletcher's volley took him by surprise.

"Darren is an improving player," said Ferguson. "Each year we have seen his performance level go up and up and it is still doing so.

"But I have to admit I did not expect that goal. It was really well taken."

Ferguson was equally delighted by a clean sheet that was achieved without the talents of Rio Ferdinand, John O'Shea and Johnny Evans, who were all ruled out through injury, plus Gary Neville, who was serving the last game of a three-match suspension.

"That is probably the most important part of the win," said Ferguson. "When we defend properly and do our jobs, as we did, it gives us a big chance of winning the league."