And defender Hyam sealed the victory with eight minutes remaining.

Tyler Morton's right-wing corner was headed towards the edge of the six-yard box by Daniel Ayala, and Hyam, with the ball behind him, brilliantly improvised to hook it into the net.

The Hornets have now failed to win in nine away league matches - a run stretching back to last season, when they were relegated from the Premier League.

They had a second-half goal disallowed for offside when Rovers were unable to clear a corner and Christian Kabasele forced the ball in following Keinan Davis' header.

Blackburn dominated the first half - Watford keeper Daniel Bachmann produced saves to deny Dolan and Ben Brereton Diaz - but came under some pressure after the interval.

Davis, on as a substitute for the injured Ismaila Sarr, caused Rovers problems as Rob Edwards' side searched in vain for an equaliser.

Their hopes of a comeback were ended by Hyam's fine finish.

The result leaves Rovers third in the Championship table and Watford seventh.

Blackburn manager Jon Dahl Tomasson:

"It was a fantastic result. I think if you look at the first 10 minutes, we had three shots on goal, we were creating chances, we were dominant in the first half, and scored a great goal with one or two touches - against a side who should be one of the favourites to go up.

"In the second half, it was good to see we were dangerous from set-pieces, scoring a goal. When you play against good players, and Watford have very good players, you have to be very focused and concentrate for 90 minutes.

"All the boys were that. We created chances in the second half and were dangerous with those transition moments. They didn't have a lot of shots on goal.

"We said that it should be difficult (for opposing teams) to come to Ewood Park. Today it was difficult and you saw that spirit and togetherness."

Watford boss Rob Edwards told BBC Three Counties Radio:

"We didn't start well, lost too many duels, and Blackburn were sharper.

"When we did have the ball we weren't good enough with it. We weren't able to break their pressure and their counter-pressing. That made for a really difficult evening, especially in the first half.

"It's something that I've spoken about with the players. There was a lack of spirit and fight in that first half. It's something that we'll have to rectify very quickly.

"No-one at every level is good enough to just turn up and win a football match. We have to earn it.

"There were quite a few of our fans who were angry and upset at the end and I can understand that.

"You can either go under or dig in and find way to turn it around."