Rovers suffered away day misery once more as they were blown away by a second half display from a lively Watford side
Gary Bowyer's Rovers were very much in the game for the opening 45 but they had no answer to the promotion-chasers in a second half in which they scored four.
Goalkeeper Grzegorz Sandomierski ensured the first half would remain goaless with a fine double save just past the midway point of the half, diving to deny Troy Deeney first and then from a ricochet off defender Scott Dann, whilst David Dunn went closest for the visitors.
But Rovers got off to the worst possible start in the second when talisman Fernando Forestieri fed Troy Deeney for the opening goal on 52 minutes.
Jordan Rhodes missed a great chance to equalise when he put a David Dunn cross over the bar and they were made to pay a minute later when Deeney added his second of the game.
The goals kept coming as Rovers struggled to cope with Forestieri as the tricky forward fed Almen Abdi for a third, then any chance of a come back was well and truly extinguished as substitute Matthew Briggs fired home from close range with 15 minutes to go.
To make matters worse for Rovers the last action of the match saw Leon Best shown a straight red card for an off the ball incident with Marco Cassetti.
Rovers have no time to ponder this game, next up is another huge game this Tuesday when the make the journey to the Den to take on Millwall.
Gary Bowyer made just the one change from the side that had defeated Huddersfield Town 1-0 in midweek.
A leg injury picked up on Tuesday to midfielder Jason Lowe meant he was unable to feature, David Dunn moving up from the bench to replace.
On a beautiful spring day it was Rovers who were bright in the opening exchanges.
Intelligent attacking play saw David Dunn have two efforts at goal in the opening 15 minutes but neither threatened Manuel Almunia in the Watford goal.
The Hornets tested the Rovers defence for the first time on 18 minutes, midfielder Almen Abdi racing along the edge of the area to tee up Fernando Forestieri but his low shot was comfortable
Rovers were awarded a controversial free kick in the area on 26 minutes when Lloyd Doyley passed back to Almunia. The indirect kick was passed the Scott Dann but he hit the rising ball over the bar.
Sixty seconds later and Sandomierski was called upon to make two excellent saves. a cross from the left saw Troy Deeney head goalwards and as he was denied by one save the ball rebounded back off Scott Dann requiring the Polish international to make a second.
Rovers were calm and composed in possession, working hard when out of it, but as Gael Givet committed himself too soon to a tackle on 38 minutes it allowed another chance at goal for Forestieri but he fired narrowly wide.
Neither side made a change at the start of the second half but it was Watford who drew first blood seven minutes after the restart.
The lively Fernando Forestieri started the move, cutting inside from the left before finding strike partner Troy Deeney and as he dragged the ball away from the challenge of Gael Givet it gave him enough room to lash the ball across goal into Sandomierski's bottom corner. The Rovers goalkeeper was at full stretch but powerless to make the save.
On the hour mark Rovers went close to a response, David Dunn chased a lost cause to keep the ball in play on the near side before crossing for Jordan Rhodes, but whilst the striker got plenty of power on the header, it flashed inches over the crossbar.
Almost immediately that missed chance would prove costly as the Forestieri/Deeney combination paid dividends once as the Italian-Argentine threaded the ball in to Deeney and he beat Sandomierski from close-range.
With Watford's tails well and truly up a third arrived on 67 minutes. The home side kept possession well before that man Forestieri showed quick feet to feed Almen Abdi in the area and he lashed the ball into the back of the net.
With 15 minutes remaining Grzegorz Sandomierski tipped over a volley from Ikechi Anya, but from the resulting corner kick Matthew Briggs added to Rovers' woes by firing home after a scramble.
With the game won the home side saw out the remaining minutes comfortably, whilst Rovers, with an eye on Tuesday's game at Millwall, gave the opportunity to rest Jordan Rhodes as he was replaced with eight minutes to go.
To compound a miserable day at Vicarage Road Leon Best was shown the red card deep into added time for an off the ball incident with Marco Cassetti. The Watford man get a yellow for his troubles but Best will miss the remaining matches of the campaign after his straight red.
WATFORD: Almunia (c), Doyley, Ekstrand (sub Briggs 70 mins), Cassetti, Anya (sub Murray 83 mins), Hogg, Chalobah, Abdi, Pudil, Deeney, Forestieri (sub Vydra 77 mins).
Subs not used: Bond (GK), Yeates, Geijo, Battocchio.
Goals: Deeney 52, 62 mins, Abdi 67 mins, Briggs 75 mins.
Booked: Ekstrand, Cassetti.
ROVERS: Sandomierski, Kane, Dann (c), Givet (sub Rekik 62 mins), Markus Olsson, King (sub Nuno Gomes 72 mins), Jones, Williamson, Dunn, Best, Rhodes (sub Morris 82 mins).
Subs not used: Usai (GK), Orr, Pedersen, Goodwillie.
Booked: Williamson, Rekik, Jones.
Attendance: 13,775 (733 Rovers fans)