Instead it was Watford who levelled the contest, when Ismaila Sarr found himself unmarked to nod home at the far post for a 72nd minute equaliser.

The Hornets thought they had a winner in the 87th minute when Joshua King slotted the ball past goalkeeper Karl Darlow – but VAR ruled the goal out for offside.

The game had all the markers of a hard-fought relegation battle with Jarred Gillett awarding seven yellow cards on his maiden Premier League game in charge.

It was a moment of history for the Australian, who became the first referee from outside the UK and Ireland to take charge in the English top flight.

In the first 90 seconds of the match, Darlow was called into action when Watford broke down the right, with King playing in Emmanuel Dennis – who took a shot from a tight angle but saw it blocked by the keeper.

In the 24th minute, the ball was played to Longstaff from Allan Saint-Maximin, before he curled a shot from 20 yards into the top left-hand corner, past Ben Foster's outstretched hands.

Watford had to wait to find an opening to try to level, but just after half an hour Darlow dived low to save a low effort from Sarr – who had driven through the Newcastle midfield to create the opportunity.

Just before the break, Newcastle had an ideal opportunity to double their advantage as Saint-Maximin was played through in a one-on-one with the goalkeeper, he tried to round Foster but the defence were able to get back, and although he found Longstaff, the goalscorer fired over the bar.

The second half was less frantic than the first, and there were no significant chances for either side despite a break from Watford when they had the numerical advantage, but Javier Manquillo was able to get back and dispossess King.

Foster was forced into a double save in the 65th minute, first to deny Miguel Almiron from range, and then from Joelinton's follow-up.

Newcastle continued to press, with Foster making a save to deny Willock after he was played in by Saint-Maximin less than three minutes later.

However, the visitors were unable to make their possession count, and Watford found the equaliser in the 72nd minute.

Almiron had given away a needless corner, which was flicked on by King to the back post, where Sarr was unmarked and able to head the ball past Darlow.

In the 87th minute, King put the ball in the back of the net after Moussa Sissoko's parried shot found the Hornets number seven, but VAR ruled the goal out for offside.

Both sides had opportunities in the remaining minutes but neither could find the breakthrough and it finished 1-1.