After a first half low on goalmouth action at both ends of the pitch, the Hornets took the lead through Andre Gray shortly after the hour mark, and United – who lacked any sort of spark throughout – rarely looked like responding.

Gray’s fellow frontman, Isaac Success, wrapped things up late on, with the Magpies’ long wait for a win in the Fourth Round of the competition extending further.

It was a much-changed Watford side who got off to the brighter start at St. James’ Park. Five minutes in, Domingos Quina let fly after finding a pocket of space on the edge of the penalty area, and Freddie Woodman had to be alert to tip the midfielder’s rising strike over the crossbar. Soon after, ex-United full back Daryl Janmaat was brought down by Isaac Hayden in more or less the same position, and Nathaniel Chalobah curled the resultant free kick just off-target.

Forward Success then directed Janmaat’s deflected cross wide of the upright, before the tempo of the game slowed considerably. The Magpies got on the ball a little more but never really looked like doing anything with it, while Watford’s own attacking charge fizzled out after a relatively purposeful opening quarter of an hour.

The Hornets did manage to get in behind United’s backline early into the second half, only for Gray to fire wildly into the Leazes End with his right foot. After another lull, the Magpies failed to make the most of a rare opening, with returning wide-man Kenedy running into trouble after gathering Jacob Murphy’s threaded pass – Rafa Benítez’s side having countered quickly following a Watford attack.

And, just a minute later, they found themselves training. With what was, in truth, the first move of any real quality in the game, Will Hughes picked out Gray’s run with a superb through ball, and the frontman fired into the near corner with an emphatic strike.

With his side now a goal down and looking to force the issue, full back Javier Manquillo embarked on a marauding run after picking the ball up just inside the Watford half. The Spaniard headed for the 18-yard box and did brilliantly to get away from three Hornets defenders – though he was helped, in fairness, by one slight deflection – before attempting to lift the ball over goalkeeper Heurelho Gomes. He did just that, but defender Ben Wilmot was in the right place at the right time to nod it clear.

Though it temporarily gave the crowd something of a lift, that moment did not prove the start of a Magpies siege. Though attacking duo Christian Atsu and Ayoze Pérez were both introduced, United still found it difficult to create anything, with Gomes more or less untroubled between the posts. It was substitute Pérez who had their only real chance of a leveller, lashing the ball over the crossbar after collecting Kenedy’s deflected cross at the back post.

And, with the rain bucketing down on Tyneside, Watford made the game safe in the final minute of normal time. After a swift Hornets break, the lively Quina made inroads down the United right and squared for Success six yards out, with the forward producing a simple finish to seal his side’s passage to the Fifth Round.