Southampton became the latest victims of goalscorer extraordinaire Erling Haaland, whose St Mary’s double propelled Manchester City to a convincing victory at Southampton’s expense.
Saints held their own in the first half, frustrating the reigning Premier League champions and threatening to score first through the lively Kamaldeen Sulemana, only to be hit by the previously subdued Haaland in the final minute before the interval.
City never looked back in the second period, as Jack Grealish scored himself before setting up Haaland for a spectacular scissor kick – the Norwegian’s 44th goal of a staggering first season in England.
Saints did pull one back through substitute Sékou Mara, who scored against City for the second time this season, but the visitors immediately restored their three-goal cushion when Julián Álvarez, just on for Haaland, converted a 75th-minute penalty.
Rubén Sellés made four changes to his starting line-up from the defeat at West Ham last time out, including a welcome return from injury for Armel Bella-Kotchap at the heart of the Saints defence.
Elsewhere, there were recalls for Ainsley Maitland-Niles, who played at right-back, Carlos Alcaraz and Kamaldeen.
Duje Ćaleta-Car, Romain Perraud, Stuart Armstrong and Mara all dropped to the bench as Saints started the match without a recognised striker.
City, meanwhile, were utilising their new 3-2-4-1 formation, with John Stones operating as a defensive midfielder, and came into the game in ominous form, winning their last seven with 27 goals scored and just two conceded in that time.
That confidence was evident from the start as the champions pieced together a sweeping move inside six minutes.
Progressing the ball from right to left through Riyad Mahrez and Ilkay Gündogan, the spare man was Grealish, whose attempted curler was beaten away by Gavin Bazunu.
Saints were not seeing much of the ball, but were doing a decent job of containing City’s superstars, and things might have got even better when an errant corner taken by the visitors presented flying machine Kamaldeen with a route to goal.
Isolated against Nathan Aké on the halfway line, a sold-out St Mary’s urged the Ghanaian to breeze past the last defender, but he seemed initially hesitant before overrunning the ball, allowing Ederson to pounce at his feet.
Kamaldeen then went eye to eye with Manuel Akanji as the winger bamboozled his man near the right touchline.
When his deep cross was retrieved by Kyle Walker-Peters, the left-back was probably too honest for his own good when he appeared to be clipped on the edge of the box but immediately climbed to his feet, which may have convinced referee Robert Jones not to award a free-kick in James Ward-Prowse territory.
Saints were holding their own, and City’s growing frustration came to the fore when Grealish claimed a penalty after chipping the ball against Ward-Prowse’s hand, but with his arm down by his side at point-blank range, any appeals were optimistic to say the least.
Haaland had been on the fringes, but the Premier League’s leading marksman is lethal in the box, and Saints were relieved when his touch let him down from a trademark Kevin De Bruyne through ball.
Then De Bruyne brilliantly helped the ball over his shoulder to Grealish before overlapping the winger and crossing to the far post, where Haaland towered above Ward-Prowse but could not direct his header on target from close range with the angle against him.
For all the visitors’ possession, chances had been few and far between at both ends. When space opened up for Roméo Lavia, the former City man might have been tempted to pull the trigger from 25 yards but instead spotted Kamaldeen wide open on the left.
Lavia’s pass invited the attacker to strike the ball first time, but it was neither a shot or a cross as his low ball into a dangerous area was out of reach of his teammates and comfortably wide of Ederson’s far post.
Just as Saints were beginning to feel pleased with an encouraging first-half display, Haaland pounced to take his remarkable goal tally to 43 for the season.
When the ball was played wide to De Bruyne on the left corner of the penalty area, the Norwegian predator was already peeling away in behind Bella-Kotchap, and duly met De Bruyne’s inch-perfect cross unmarked, gleefully heading home from six yards in the final minute before the break.
It was the worst possible time for Saints to concede, undoing so much good work, and City resumed after the interval with a spring in their step.
Gündogan could hardly have come closer to doubling the lead three minutes into the second period, aiming to place one into the top corner that left Bazunu rooted and relieved to see the ball sail inches wide.
Instead it would be Grealish who effectively put the game to bed with City’s second goal ten minutes later.
Released by Haaland, the England international was initially denied by Bazunu but was alert to the rebound, firing the ball back into the net before the goalkeeper had to time to set himself.
Sellés responded with a straight swap in midfield, as Armstrong replaced Elyounoussi, but with Mara and Moussa Djenepo ready to be introduced soon after, Saints were hit by a killer third.
Again Grealish was involved, carrying the ball down the left and crossing for Haaland, albeit slightly behind him.
What followed was a piece of world-class finishing, as the striker adjusted his body to fire a sublime scissor kick back across the helpless Bazunu, who never stood a chance of saving it.
It would prove to be his last touch of the game, replaced by Álvarez, while Mara and Djenepo were summoned by Sellés, who had been hoping to make the changes before the goal.
Both substitutes made an impact, combining to temporarily reduce the deficit when Djenepo’s nimble footwork set up Mara to score his first Premier League goal, a crisp low finish from 12 yards to add to his Carabao Cup strike against the same opposition back in January.
Saints’ slither of hope was immediately extinguished when Walker-Peters desperately lunged in with De Bruyne primed to shoot, catching the Belgian and leaving Jones no option but to point to the spot.
With Haaland watching from the bench no doubt aggrieved at missing the opportunity to complete his hat-trick, his replacement Álvarez buried the spot-kick straight down the middle.
It was harsh on Saints, whose approach had frustrated City for the vast majority of the first half, but the hosts, like most before them, had no answer when the champions turned up the heat.
Southampton: Gavin Bazunu, Ainsley Maitland-Niles, Kyle Walker-Peters, Jan Bednarek, Armel Bella-Kotchap, Theo Walcott (Romain Perraud 80), Roméo Lavia (Ibrahima Diallo 80), Mohamed Elyounoussi (Stuart Armstrong 61), James Ward-Prowse [c], Carlos Alcaraz (Moussa Djenepo 69), Kamaldeen Sulemana (Sékou Mara 69).
Unused subs: Paul Onuachu, Duje Ćaleta-Car, Sam Edozie, Alex McCarthy.
Manchester City: Ederson, Nathan Aké (Sergio Gómez 81), Rúben Dias, Manuel Akanji, Rodri (Kalvin Phillips 81), Ilkay Gündogan [c], Kevin de Bruyne, John Stones (Kyle Walker 56), Riyad Mahrez (Bernardo Silva 56), Jack Grealish, Erling Haaland (Julián Álvarez 69).
Unused subs: Aymeric Laporte, Cole Palmer, Rico Lewis, Stefan Ortega.
Goals: Haaland (2), Grealish, Álvarez.