There were signs the game was already turning in the Hornets' favour before Tom Cleverley headed in his tenth of the season six minutes before the interval and the home side's supremacy was deservedly underlined by second-half strikes for Heidar Helguson and Don Cowie.
Of perhaps greater importance for Watford's longer-term aspirations this term was the role of Martin Taylor.
Malky Mackay's men had shipped 12 goals in their previous four outings and the former Birmingham City centre-half was given his debut after signing on a free transfer last week and the Hornets' backline looked far more solid as a result. The same cannot be said of the Blades.
All three goals were defensively poor and all three came after talismanic skipper Chris Morgan was forced out of the contest with a first-half injury. Ironically, it took a fine save from Scott Loach to prevent Morgan from heading the Blades in front, but soon after he was limping to the touchline to be replaced by Jonathan Fortune.
It took an equally good stop from Mark Bunn to prevent Helguson scoring within a minute of Morgan's chance, but six minutes before the break the Iceland international's clever movement caused the Blades defence to freeze as Taylor lofted a ball through and Cleverley beat Bunn to the bounce to make it 1-0.
Helguson should have doubled that lead within 60 seconds of the restart when he was played through one-on-one with Bunn.
But the on-loan Queens Park Rangers striker made no mistake when more shambolic defending presented him with another gilt-edged opportunity on 55 minutes.
The Hornets' third 20 minutes later had a touch of good fortune about it, but the Blades will still be asking themselves why Cowie's free-kick from all of 40 yards on the left was not dealt with before it beat Bunn at his far post.