The three points were sealed when fellow debutant Neal Maupay expertly rounded Ben Foster in the Watford net before tapping home in the 77th minute.

Watford’s impressive record on the opening day, having avoided defeat on the first match of each of the last 12 seasons, was brought to an end by Albion who recorded their first win at Vicarage Road in five attempts.

The Hornets enjoyed most of the possession in the first 10 minutes and it was Foster who was the first to be properly tested first after Martin Montoya sent in a cross, but Jurgen Locadia’s effort was straight at the goalkeeper.

It was Albion who then had a second chance as the ball fell to Davy Propper but his long-range effort sailed over the bar.

The Hornets had a shout for a penalty when Gerard Deulofeu went down in the area under a challenge from Shane Duffy, but referee Craig Pawson ruled play on without consulting VAR.

In the 29th minute Jose Holebas floated in a cross which fell to Gross who volleyed the ball towards Glenn Murray four yards out, but before the it reached Brighton’s number 17, Doucoure deflected the ball into his own net.

Watford’s Kiko Femenia sent in a long-range effort at the other end with his side looking for an equaliser but the strike went just over.

Mat Ryan was called into action from a Holebas free-kick as the Australian tipped the ball over the bar, from the effort just outside the area after Lewis Dunk brought down Will Hughes.

In a bid to find the equaliser, Watford boss Javi Gracia brought on Roberto Pereyra, who scored twice against Brighton in the opening game of last season, in place of Deulofeu.

Watford looked to attack at the start of the second half, forcing Ryan to make an instinctive reaction save with his legs to deny Andre Gray.

VAR was called on for the first time at Vicarage Road in the 59th minute for a handball in the area after a Pereyra free-kick was hit straight at the wall.

Brighton substitute Andone doubled his side’s lead with his first touch after coming on in the 64th minute, turning the ball past Foster from a Propper cross.

As Watford looked to pull one back, Foster was called on to gather the ball from a Craig Dawson header on his club debut, but the effort went straight at the keeper.

Albion sealed victory in the 76th minute, when a long ball was expertly played through from Dunk to Maupay who took the ball round Foster before slotting home.

After setting up Maupay, Dunk was called on at the other end, diving down to make a clearance off the line to deny Dawson.