Watford suffered an agonising 2-1 defeat away to Doncaster Rovers as they were left to rue one of the worst refereeing decisions seen in recent memory at the Keepmoat Stadium.

A petulant kick-out by Mathias Ranegie saw the Hornets reduced to ten men inside the opening 20 minutes and Donny capitalised midway through the half through a fine Chris Brown header.

But Watford will attribute a significant part of the blame for their defeat to referee Chris Sarginson after he inexplicably failed to award the visitors a penalty and send off goalkeeper Sam Johnstone just before the break.

The Golden Boys responded well following the restart and equalised through Ikechi Anya’s confident finish on 68 minutes.

However, fatigue set in and Watford were defensively disorganised as Doncaster spent most of the final 20 minutes in and around the opposition penalty area.

And the pressure eventually told in the third minute of injury time when Billy Sharp capitalised when Jonathan Bond failed to deal with a long-ranged shot.

The Hornets made two changes, both of which were forced. Manuel Almunia missed out due to illness and Sean Murray’s groin problem resulted in a start for Alexander Merkel.

The opening quarter of an hour was largely uneventful but the Hornets edged the play. Ranegie had a knock-down which couldn’t be reached by a team-mate and he almost released Troy Deeney with a through-ball.

The first real chance also went the visitors’ way when Merkel had a low drive saved from the edge of the area following a one-two with Deeney.

But the momentum shifted on 19 minutes when Husband outmuscled Ranegie off the ball and after the pair tangled, the Watford striker kicked the left back. The referee didn’t appear to see the incident and the linesman didn’t flag but they came to the correct decision as the Sweden international was given a straight red card.

Doncaster did the right thing as they subsequently kept the ball patiently and the opening goal came five minutes later. James Coppinger delivered a superb cross from the right and Brown headed powerful into the goal.

Rovers’ pressure increased as David Cotterill shot wide and then after Mark Duffy had a shot stopped, Deeney did excellently to block his follow-up.

The Hornets did have their own shot blocked half an hour into the contest through Gabriele Angella and Ikechi Anya’s low cross into the six-yard box was cleared.

Then in the 41st minute came one of the worst refereeing decisions seen during a Watford match in recent years. Deeney dived to block Johnstone’s clearance following a short back-pass and as the striker got to his feet, he was pulled down by the keeper yards from goal in a rugby tackle-like fashion. It was one of the most blatant penalties you will see and a certain red card but the referee inexplicably failed to point to the spot.

All of the talk in the press room at half time was about the incredible decision by referee Sarginson.

The second half was a balanced affair and the visitors should have scored the equaliser seven minutes after the restart. Merkel struck a lovely free-kick from 20 yards which rebounded off the crossbar and the ball bounced up too quickly for Deeney to direct it into the net inside the six-yard area, with the ball instead sailing over.

Like the first half, the momentum of the match shifted significantly in a one-minute period.

Doncaster should have gone 2-0 up when a neat through ball from Richie Wellens released Billy Sharp and the striker should have got a shot away before Daniel Pudil made a superb last-ditch tackle.

The Golden Boys then went straight up the other end and substitute Fernando Forestieri beat his man on the left flank before picking out the excellent run of Anya with a fine lofted pass and the Scotland winger finished confidently into the bottom corner.

Watford had gone to a 4-2-2-1 formation following the introduction of Forestieri, with the Argentine playing wide left and Anya on the right of Deeney, and the decision worked well in terms of the goal.

But it was all one-way traffic in the final 20 minutes as Doncaster laid siege to Watford’s goal.

Moments after the equaliser, Duffy’s lovely cross picked out Sharp at the far post but he couldn’t direct the ball in from close range.

Watford goalkeeper Bond had a mixed final quarter of an hour. He fumbled a cross under pressure which almost led to a goal for Sharp but he also made a superb save to deny Wellens.

Doncaster missed a host of excellent chances in the second half and Brown should have scored when he flicked the ball wide from four yards out.

Watford’s defensive organisation was chaotic to say the least – almost nonexistent.

Keegan beat Bond with a shot in the final ten minutes but this time Angella cleared off the line, Duffy had a free-kick well saved and Keegan shot wide from inside the area.

It looked as though Watford had just about survived but in the third minute of injury-time, Bond wasn’t able to hold on to Duffy’s low shot from outside the area and Sharp was able to slide in to score the deciding goal.

It was an agonising way to lose but Watford could have few complaints as the winning goal had been coming for Doncaster.

Doncaster line-up: Johnstone; Coppinger, Quinn, Meite (McCullough 45), Husband; Duffy, Keegan, Wellens, Cotterill; Brown, Sharp.

Subs: Maxted, Furman, De Val, Robinson, Stevens, Bowery.

Watford line-up: Bond; Doyley, Cassetti, Angella; Anya, Battocchio (Faraoni 88), Tozser, Merkel (Forestieri 59), Pudil; Deeney, Ranegie.

Subs: Woods, Belkalem, McGugan, Neill, Hoban.

Referee: Christopher Sarginson.

Attendance: 6,581 (429).