Apart from two consolation goals after the Championship side took their foot off the pedal late in the game, the Saints who were never really in the hunt.
Giant killing seemed to be on the cards from the outset as Bruce Dyer twice went close before finally finding the net after 39 minutes.
Dyer headed firmly into the net from Neal Ardley's cross, but the visitors' marking was atrocious.
Six minutes into the second half following another corner by Ardley, James Chambers was there at the far post to plant the ball home in a crowded goalmouth.
Watford continued to press and in a sense let
Dyer showed tenacity on the left working his way through two clumsy challenges before pulling the ball back for Chambers to ram in the third from 12 yards out.
With a 4-0 lead,
Almost immediately
Two minutes from time the visiting fans were given a crumb of consolation when Danny Higginbotham crossed for Brett Ormerod, the most determined
Watford: Richard Lee, Sean Dyche, James Chambers (Ashley Young 71), Neil Cox (Jay DeMerit 85), Jermaine Darlington, Lloyd Doyley, Brynjar Gunnarsson, Neal Ardley, Gavin Mahon, Bruce Dyer (Hameur Bouazza 75), Heidar Helguson. Subs not used. Alec Chamberlain, Scott Fitzgerald
Watford were to defeat another Premiership side, Portsmouth (3-0) in a home Quarter-Final before narrowly losing to a Steven Gerrard inspired Liverpool in a two-legged Semi-Final in January 2005.