Ruud blow for United

"He is a man who can win a game for us," said the Scotsman. "It would be a bitter blow, but we will get on with it. We have other players who can replace him and different options." Ferguson has rushed Forlan back from international duty with Uruguay after initially allowing the player to miss the showdown at Villa Park although he will not join his team-mates until tonight.

Despite the uncertainty over van Nistelrooy's fitness, the Old Trafford boss today challenged Arsenal's supremacy ahead of the semi-final by declaring that United have "turned the corner".

Ferguson believes his team are finally emerging from the rut that ruined their Premiership title chances and saw them crash out of the Champions League.

"I believe the team have turned the corner," he said. "The draw at Highbury last Sunday saw us grow in confidence as the game progressed.

"It's the first time in a few weeks I've been able to choose the defence I wanted in consecutive matches."

The Old Trafford club have come out fighting ahead of the crunch match by also insisting their London rivals are playing "catch-up" in terms of global appeal and financial muscle.

United admit the Gunners have overtaken them on the pitch this season, but say their Highbury rivals will never be able to challenge their financial dominance.

Finance director Nick Humby said: "They have caught us up competitively on the field this season. But they are playing catch-up in a number of areas - not just in stadium size but the whole brand and exploitation of the whole brand around the world."

In a demonstration of United's continuing financial muscle, they were today linked with a £10million move for Dutch midfielder Rafael van der Vaart, who plays for Ajax.

Thierry Henry looks certain to miss the match as Arsene Wenger juggles his squad for an historic Treble bid.

Robert Pires is also a candidate for a substitutes' role tomorrow. Gael Clichy continues as Ashley Cole's deputy in defence.