The Spaniard was probably not expecting a ticker-tape welcome when the club's owner Roman Abramovich hired him as an interim manager after Roberto Di Matteo's harsh sacking last week, but the depth of ill feeling directed towards the former Liverpool manager has been unprecedented.
His first match in charge, against champions Manchester City last Sunday, was greeted with boos, unflattering chants and "Rafa Out" signs.
Wednesday's dismal draw with local rivals Fulham was played out in almost complete silence as a pall of gloom appeared to descend on the club that just a few weeks earlier was top of the Premier League and playing sparkling, attacking football.
They have managed just four points since, have been embroiled in racism allegations against referee Mark Clattenburg, of which they have since back-tracked, are on the verge of a Champions League exit and sacked the manager that took the club to Europe's top club trophy.
"Two clean sheets is something positive but still I want to score goals and be more offensive," Benitez said after the draw against Fulham which extended Chelsea's dismal run without a league win to six.
"We have some confidence because we don't concede and if we can build from there I will be happy."
Captain John Terry, midfielder Frank Lampard and striker Daniel Sturridge are all unlikely to be fit to face West Ham with Sturridge's absence meaning misfiring Fernando Torres will again be shouldering his side's attacking options.
United should overwhelm Reading in Saturday's evening kick-off, although they will be wary after their previous away league game ended in a 1-0 defeat at Norwich City.
