I dont see how United would win with that formation. It would be a repeat of the semi last year where United hardly had a touch of the ball.
Scholes scored a hit and run shot and that was the only threat coming from United. Very important to note, this is a very different side that lost to United last season.
On Wednesday, United could not touch the ball. That was with an attacking formation. If they played a defensive formation, they would have been even less of a threat to this superior Barca side.