With the Glazers at Old Trafford for the first time since November, United could not have picked a better time to record arguably the most significant win of their wretched season.
United's lack of midfield options was laid bare - Ryan Giggs partnering John O'Shea in the centre, with Kieran Richardson and Darren Fletcher deployed left and right. Hardly a quartet to strike fear into opponents, and so it proved.
The first-half was as combative as meetings between these two old foes always are, but there was little fluency.
Liverpool
United's best opening came just before half-time when Giggs found Ruud van Nistelrooy, who then lost his footing.
Predictably, there were few chances but Cisse was guilty of the worst miss in the 63rd minute when he blasted over.
United abandoned their 4-4-2 system and played the second half with three up front and three in midfield having taken off O'Shea in favour of Louis Saha.
The gamble ultimately paid off.
Liverpool
Gerrard wasted the free-kick and a minute later United had the ball in the
Giggs lifted the ball into the area and Ferdinand rose to power a header which Jose Reina could only palm into the top corner. Cue mayhem.’