New first-team coach Paulo Sousa chose to watch the game from the stands - leaving Gareth Ainsworth in charge - but by the end of it the two-time Champions League winner must have had his head in his hands after Rangers were comprehensively and deservedly beaten.
Rangers may have one of the richest board of directors in football, but money cannot buy you desire and a willingness to battle – and those wearing blue and white hoops were abundantly short of those qualities from the outset as Watford took charge and had the game won by half-time.
Tommy Smith set the home side on their way with his eighth of the season from the penalty spot in the 26th minute after he was clumsily barged in the back by Damion Stewart.
The Rangers backline were again at fault for Watford's second eight minutes later.
They couldn't do much about Lee Williamson's fine 25-yard free-kick that rebounded off a post, but their failure to react to the loose ball allowed Jon Harley to cross the ball back in for Darren Ward to score the first goal of his second spell at Vicarage Road.
Stewart's first-half nightmare continued just before the interval when he was shaken off the ball with ridiculous ease by Smith, who pulled the ball back for Williamson to score his third in four games with a low drive past the unsighted Radek Cerny.
A comeback never seemed likely - and so it proved - and the visitors' miserable afternoon was completed ten minutes from time when Fitz Hall received a straight red card for a late and high challenge on Will Hoskins.
This was a vital victory for Watford as, not only did it lift them out of the relegation zone and end a run of five straight league defeats, but it boosted caretaker manager Malky Mackay's chances of securing the job on a permanent basis.