Those losses had checked the Reds' own promotion hopes and Valerien Ismael's side now find themselves seven points adrift of the play-offs.

Watford were thankful for Kiko Femenia's near-post intervention to stop Victor Adeboyejo setting up Conor Chaplin early on.

Right-back Femenia then launched a long-ranger that only just cleared the crossbar at the other end.

Good defending from Mads Andersen prevented Andre Gray from testing Barnsley goalkeeper Jack Walton before Cauley Woodrow headed a Chaplin cross over.

Callum Brittain's bizarre decision to stick out an arm when Deeney crossed in the 26th minute ended up costing Barnsley. The ball reared up off his leg but Brittain's right arm was in such an un-natural position that referee Tim Robinson had no hesitation in pointing to the spot.

Deeney took the penalty and blasted it straight at Walton, who found it simply too powerful to keep out. It was the Hornets captain's fifth goal of the season – and his fourth spot-kick.

That pepped up Watford and it was not long before Gray took the ball round Walton, who had come out of his area. Andersen failed to deal with the shot from an angle that followed but Michal Helik prevented it from crossing the line.

It was all Watford as half-time approached, with Femenia launching another long-ranger just over and Walton doing well to foil Gray after Ken Sema had played him in.

Barnsley were relieved Gray failed to double the lead two minutes before the break. Ismaila Sarr's pace down the right opened up their defence but Gray could only dink over Walton and wide from 10 yards.

Sarr began the second period with some magic on the byline that saw three defenders beaten but the hapless Gray got in the way of the pull-back for Sema that followed.

Callum Styles fired a rare Reds reply wide before Gray had a goal ruled out for offside. Will Hughes saw a deflected effort from distance ping back off a post in the 57th minute but the flag went up as soon as Gray despatched the rebound.

Watford goalkeeper Daniel Bachmann pulled off a fine reflex save to deny substitute Carlton Morris but there had already been a foul in the build-up.

Bachmann then made an even better stop to prevent Francisco Sierralta from scoring the own goal of the season with a flying header.

William Troost-Ekong passed up a late chance to wrap up victory by flicking substitute Philip Zinckernagel's cross across goal and just wide.