Blackburn are still searching for their first away win of the season after Edo Kayembe fired Watford to a 1-0 victory with a 71st-minute penalty.
Rovers, managed by former Watford captain John Eustace, had two great chances to take the points and cement a place in the top six but Dominic Hyam and Andreas Weimann were left cursing their luck.
Those misses came back to haunt them when midfielder Kayembe blasted home from the spot to stretch Watford’s unbeaten home run to 12 matches.
Watford, coming off the back of two defeats on the road, made the early running.
But Rovers were unlucky not to go ahead in the ninth minute. Home goalkeeper Daniel Bachmann, picked despite there being a question mark over his fitness and form, fumbled a right-wing cross from Lewis Travis and the ball fell into the path of Hyam.
The centre-back crashed his close-range shot against the underside of the bar and the ball struck the goalline without going over before Bachmann redeemed himself by saving Makhtar Gueye’s follow-up header.
That stung the Hornets into action and, midway through the first half, Tom Ince crossed to Chilean defender Francisco Sierralta, who saw his close-range header blocked.
Kwadwo Baah passed up a fine chance to give Watford the lead in the 34th minute.
Midfielder Georgi Chakvetadze, making his 50th appearance for the club, fired a pass that sent wing-back Festy Ebosele racing down the right. His cross found Baah unmarked in the box but the young striker rushed his shot and volleyed high over the bar.
During three minutes of first-half stoppage time, Rovers survived a strong penalty appeal as keeper Aynsley Pears appeared to take out Ryan Porteous at waist height. But referee Darren England was not interested – probably correctly.
Blackburn ran things for the opening 10 minutes of the second half, but were confined to a blocked shot from Geuye.
Then, two minutes before the hour mark, Rovers missed another great chance to go ahead.
Todd Cantwell’s through ball found Weimann unmarked in the box, but the veteran striker should have done much better than just lift his shot onto the roof of the net.
England had to step in and calm down a flare-up after Cantwell was booked for fouling Chakvetadze in the 68th minute.
The Georgian midfielder appeared to kick out as he lay on the ground but peace was restored – and three minutes later Watford took the lead.
Ryan Hedges, scorer of Blackburn’s goal in their victory at Vicarage Road last season, handled in the box and England had no hesitation in pointing to the spot.
After seemingly endless conversations between referee and players, Kayembe’s left-footed shot sent Pears the wrong way as the keeper dived to his right – Watford’s first scoring attempt on target.
With eight minutes of normal time left, substitute Rocco Vata could have made it 2-0 but shot into the side netting from a few yards out.
Blackburn, with all five substitutes on the field, stormed back into the attack, but those missed chances ruined their day.
