Pérez, whose goal earned the Magpies three points at Leicester City last week, proved decisive once again for the hosts, guiding home a low shot before sliding home a second to cap what was a dominant opening 45 minutes from Rafa Benítez’s side.

Saints pulled one back after the break through substitute Mario Lemina but couldn’t quite muster a leveller despite their endeavours, leaving Pérez to glance home and complete his treble with just four minutes left on the clock, rounding off a memorable evening for the 25-year-old.

Saints survived an early penalty claim when Pierre-Emile Hojbjerg appeared to handle Isaac Hayden’s hooked effort in the box, and most of the early pressure came from the hosts. Matt Ritchie dragged an attempt wide and Miguel Almirón forced Angus Gunn to tip his cross-shot away.

Midway through the first half, Almirón burst past James Ward-Prowse just inside his own half as Newcastle looked to counter. Saints’ midfielder was his side’s last man and, with Rondón not far behind, Almirón looked set to sprint clean through on goal. But though Ward-Prowse cynically stepped across the Paraguayan and blocked him and halted the attack, referee Anthony Taylor deemed the challenge only worthy of a yellow card, incensing many inside St. James’ – including United coach Mikel Antia, who was sent to the stands.

But the decision only seemed to buoy Benítez’s men, as barely five minutes later they took a deserved lead. It owed much to the industry of Isaac Hayden, whose thumping tackle presented the chance, but when Pérez picked the ball up there was still plenty to do. He ran at Southampton’s defence but a challenge wasn’t forthcoming, so the Spaniard picked his spot with a deft low finish which clipped the post on its way in.

Just after the half hour, it was two, thanks to another quick break from United. Rondón set off down the left and sent over a wonderful cross to the back post which Pérez dispatched, sliding in and lifting the ball over Gunn’s outstretched arm to double the advantage.

That goal took Pérez into the top ten on United’s list of all-time Premier League goalscorers, a reward his influence in this current Magpies team merits. Fellow frontman Rondón could have netted before the break, but saw his shot blocked.

Saints came out fighting after the restart and Maya Yoshida glanced wide as Ralph Hasenhüttl’s men rallied. He brought on Stuart Armstrong and Lemina to bolster their midfield, which had struggled against Hayden and Ki Sung-yueng. Ward-Prowse whipped in a free kick, but Martin Dúbravka held it with ease.

It had been a subdued start to the second half from the hosts, who did go agonisingly close to adding a third when Ki blasted a long-range effort off the base of Gunn’s post. But Saints had shown their intent, and they were rewarded for it when Lemina curled home from just outside the box to reduce the deficit just before the hour.

It set up an intriguing final 30 minutes. With Southampton in the ascendency, Newcastle lost Almirón to injury and the visitors continued to pile on the pressure, with Yoshida hooking Nathan Redmond’s cross over the bar.

Then, with Fabian Schär also succumbing to injury, United went close to adding a third against the run of play. Substitute Christian Atsu’s cross was headed clear by Ryan Bertrand but only as far as Hayden, who connected with the volley superbly. It took a deflection on its way through, but somehow Gunn got a fingertip to it to keep it out.

But late on, after more Southampton pressing at the other end, Pérez made the game safe. Ritchie’s brave diving header may have been heading towards goal but the frontman helped it on, nodding it beyond the reach of Gunn to seal his first treble for the club, capping a fine individual display and earning a fine ovation from the Magpies faithful.