The reason for the Hornets' amazing fall from grace can be summed up by numerous statistics, but the most damning is a staggering tale of woe at Vicarage Road which reads just two wins in 16 league outings.
Add to that a record of just one win in their last 13 matches, a team bereft of belief, ideas, energy and quality and a manager who seems to have no idea how to arrest the slide, it was obvious why the final whistle at the end of this lack-lustre spectacle was greeted with a loud and sustained chorus of boos from the home faithful.
On this evidence there is no way Watford , even if they do sneak into the end-of-season lottery, will reach Wembley, let alone bounce back to the top-flight at the first attempt. Not that should detract from Scunthorpe's display. The Iron, who are already relegated outclassed their opposition, and looked comfortable throughout.
Nigel Adkins' men could have been forgiven for turning up and going through the motions but, after a particularly dull first half, United sensed their opportunity after the restart.
Jonathan Forte, twice, and Matthew Sparrow had chances before Forte supplied the 68th-minute cross which allowed Paul Hayes to get in at the near post and head in the winner.
The goal sparked jubilant celebrations infront of the travelling United fans, who got behind their side throughout.
The best Watford could muster was a mazy 40-yard run by replacement Lionel Ainsworth that took him past five opponents and ended with a shot that was deflected wide.
Watford didn't even manage a shot on target, and Scunthorpe celebrated their second successive win since being relegated from the Championship.