Watford 0-4 West Ham
Watford 0 - 4 West Ham
West Ham recorded back-to-back away wins for the first time since December 2007 by thrashing Watford.
James Tomkins opened the scoring for the Hammers with a powerful back-post header from Matt Taylor's corner.
Joey O'Brien prodded home after bustling his way into the penalty area, before Carlton Cole slotted home Herita Ilunga's low cross.
And Scott Parker added the fourth late on to leave Sean Dyche still searching for his first win as Watford boss.
The Hornets almost went ahead in the first minute when Robert Green fumbled John Eustace's long-range drive, but the England keeper recovered to beat Marvin Sordell to the rebound.
The visitors soon took the lead when Taylor's corner, which he had earned when his sweetly struck 30-yard free-kick was deflected around the post, was met by the head of Tomkins at the back post and found its way to the opposite corner of the net.
Watford crafted chances of their own, Mark Yeates' through ball released Sordell, whose goalbound effort produced a fine reflex save from Green and Eustace kept the Hammers keeper working with his stooping header from a Yeates corner.
But the visitors continued to be a threat, with Winston Reid and Cole going close before Jack Collison and O'Brien combined well for West Ham's second.
It looked like the chance had passed when Collison was closed down while cutting in across the penalty area, but the ball broke nicely for him and he placed the ball past Loach.
Watford started the second period brightly with Green fumbling a Sordell drive around the post, but the Hammers struck back when Kevin Nolan, playing in a forward role, was able to find Ilunga, who fizzed in a low cross which Cole converted to notch his first goal of the campaign.
And Parker, who had given a warning of what was to come with an off-target effort, completed the rout in injury time with a tidy finish from the edge of the area.