The Mexican's second-half brace came after Giggs and Rooney had got the ball rolling for an emphatic Red Devils side with Hughes' consolation the only blot on the copybook
Ryan Giggs' penalty was added to by Wayne Rooney's driven strike before Chicharito put the gloss on the scoreline with a quick-fire double. Aaron Hughes scored late on but it meant little to the Cottagers, who were poor throughout.
United began in typically blistering fashion as they mustered up a chance immediately from the outset as Rooney engineered a chance, which was eventually deflected wide for a corner.
Rooney's in-swinger hit the hand of Hughes as he jumped with Chris Smalling and Giggs, who was elected as the spot-kick taker after Rooney's recent misses, dispatched with aplomb despite the best efforts of Mark Schwarzer.
Sir Alex Ferguson's side were incisive with their passing in the final third and an eye-of-the-needle through-ball from Rafael found the overlapping Nani, whose cutback to Rooney was ultimately fired onto the bar via Schwarzer's finger-tips.
As the Red Devils drove on, Giggs and Patrice Evra linked up well down the left and when the Welshman freed the latter, Damien Duff stuck out his arm to divert the ball out for a corner, but to the astonishment of the United players and Old Trafford crowd, Mark Clattenburg refused to award another penalty.
Rooney was then denied by Schwarzer once again, with the Australian veteran desperate to give his side a fighting chance in the second period, while Nani also went close on two occasions but after working himself some space, he fired wide each time.
After Dimitar Berbatov wasted a fantastic chance for Martin Jol's side shortly after the break, the Cottagers were duly and emphatically punished by a quickfire double.
Rooney, who was at the centre of everything good about United's display was slipped in by a wonderful Anderson sliderule pass and after controlling and checking back inside Hughes, the 27-year-old smashed a ferocious effort past the hapless Schwarzer.
Jol and Schwarzer will quite rightly be asking questions of the defence, as they stood off Nani and Rooney, leaving the latter with the simplest task of locating Chicharito in the six-yard box, and the predatory Mexican made no mistake.
The space offered to United was frightening as they attacked at will but although the visitors' defending was slack, to say the least, Chicharito's effort was fortuitously diverted past his own keeper by Hughes, who had a torrid night defensively.
Hughes proved no match for United's illustrious strikeforce at times but showed his fellow teammates how to do it in front of goal as he grabbed a consolation strike when he headed Giorgos Karagounis' corner home at David de Gea's near post, but it was little consolation for the well-beaten Londoners.