Pérez applied a deft finish to fellow substitute Ki Sung-yueng’s free kick with 25 minutes remaining at St. James’ Park, nodding in to give Rafa Benítez’s side a long-awaited victory over a side who had been in fine form this term.

Newcastle had to weather the storm to make sure of the welcome three points, with Watford carving out – and wasting – a collection of opportunities, but in the end Pérez’s excellent header proved decisive.

A flowing first period produced a host of chances, with the visitors carving out the majority of them. The first fell to skipper Adrian Mariappa, who headed Jose Holebas’ corner into the crowd before dragging another attempt, which fell kindly at his feet after Will Hughes’ was blocked, past the post.

Mo Diamé tested Ben Foster with a powerful drive but Javi Gracia’s men looked lively on the break, with Isaac Success’ power and Gerard Deulofeu’s pace proving a lingering threat. A counter attack was built down the left by Holebas, Roberto Pereyra and Success, who squared for the unmarked Deulofeu to pull a first-time effort wide.

Though Mariappa did well to retreat and slide in to deny Kenedy a shot on goal, the Hornets took little time to respond with an attack of their own and this time, Deulofeu found even more space to latch onto Success’ raking ball across to him before firing wide of the advancing Martin Dúbravka’s goal.

A pair of free kicks, from Etienne Capoue and Jonjo Shelvey, flew over before Watford squandered two more openings, with Deulofeu blasting wide and Success seeing his strike tipped past the upright by the United stopper.

Magpies forward Yoshinori Muto hobbled off in the half’s dying moments, with Pérez summoned from the bench, before Benítez replaced Jamaal Lascelles with Fabian Schär at the break. The Swiss centre half almost made a telling contribution within seconds of his introduction, when his dangerous centre was hacked over the bar with Salomón Rondón lurking.

But Watford, who came into the contest in eighth place in the Premier League, went even closer just before the 50-minute mark. Success burst past DeAndre Yedlin down the right and squared for Pereyra, whose shot cannoned off the crossbar with Dúbravka stranded. The Slovakian then got down well to deny Deulofeu, whose cross-shot looked to be sneaking in.

Craig Cathcart headed a Holebas corner over after a wayward Kenedy shot from range, but the Magpies began to rally. Ki Sung-yueng replaced the injured Jonjo Shelvey and, just after the hour, a deadlock-breaker finally arrived. It was Newcastle who struck and it was Pérez who got it, getting his head to Ki’s whipped delivery to send St. James’ into raptures.

Watford sought an answer, immediately sending on Andre Gray in place of Deulofeu, but the tide had turned, with on-loan forward Rondón finding himself with a free header ten yards out and a chance to make it two. With Foster stranded, the Venezuelan met Paul Dummett’s cross, but sent it wide of the target.

A scramble in the visitors’ goalmouth almost heralded another, but it took a fine piece of defending at the other end to preserve the advantage. Success again got past his man and squared it but, just as Gray looked to pull the trigger in front of goal, Kenedy arrived at just the right time, sliding in to smother the shot.

Stefano Okaka blazed over a chance to level at the death but ultimately, it was the United substitutes who made the difference. Schär and Ki made their presences felt in a much-improved second half display, and the latter’s assist for Pérez’s winner was crucial as the Magpies finally recorded a first win of the campaign.