Watford required just four minutes to take the lead.

Rotherham goalkeeper Jamal Blackman had made a good block to deny Stipe Perica but the Millers could not cope with the corner.

Deeney flicked on Ken Sema's delivery and centre-back Kabasele stuck out a long leg to net from five yards.

It took a further 11 minutes for the Hornets to double their lead from even closer range, with Millers defender Wes Harding providing an unwitting assist by slicing Kiko Femenia's cross towards his own goal.

The ball would have dropped the other side of Blackman's left-hand post but Deeney had anticipated and pounced from two yards for his second goal of the season.

Tom Cleverley fired two chances from the edge of the box over the Rotherham bar before Ben Wiles appeared to trip Ismaila Sarr in the box but the Watford man had already been flagged for offside.

Paul Warne's visitors were struggling to create anything meaningful at the other end but Blackman was able to claim Jeremy Ngakia's cross after Watford unhinged their defence down the right flank and Kabasele could not hit the target with a header from Cleverley's free-kick.

Watford's next attack wasn't long in coming as Sema sprinted into space on the left but Angus MacDonald was in the way of Deeney's shot and Nathaniel Chalobah fired the rebound wide.

Michael Ihiekwe did well to stop Sarr setting Perica up for the third but the half-time whistle must had come as a relief for the over-worked Millers defence.

Rotherham replaced Jamie Lindsay with Matt Olosunde during the break and immediately looked more dangerous, with Kyle Vassell forcing Ben Foster into what was to be his only save of the evening with an angled drive.

Kabasele was in the way of Michael Smith's shot after Cleverley had been robbed of possession by Matt Crooks and within a minute MacDonald had headed narrowly wide from Daniel Barlaser's free-kick.

The speedy Sarr was the only Watford man causing problems at the other end and Billy Jones was booked for fouling him and immediately subbed.

Crooks fired over as Rotherham searched once more for a way back into the game and Perica could have ended the contest in the 84th minute but shot across goal and wide from Sarr's pass.