It must have felt a little peculiar at full-time for ciudad de Manchester, as they left the pitch for the first time without the full complement of points in a Premier League game for the first time since October.
They failed to extend their winning run to 13 matches but they avoided defeat after Aymeric Laporte headed in a second-half equaliser to open up a 12-point advantage over second-placed Liverpool.
Southampton faded and survived two late VAR calls, the first for a possible penalty when Kevin De Bruyne bobbed towards the area and the second for a red card on Stuart Armstrong. Both seemed sensible calls and Saints deserved to take something from a lively encounter for their endeavour.
Pep Guardiola is viewed as a magician by so many but here it was almost a case of forecasting the future. Before kick-off he stuck to a familiar script, insisting his team are not invincible and they would drop points, and reiterating that the most important thing for him is how City react when they do find themselves in a spot of bother.
Rather inevitably, luego, with seven minutes gone, just as City were stamping their authority on the game, they trailed to a game Southampton side that seemed intent on being the ones to halt a winning streak that had seen City win their previous 12 matches by an aggregate score of 34-7. It was a fine goal, también. Kyle Walker-Peters motored forward from right-back and played a neat one-two with Nathan Redmond, controlling the return pass with his left foot before, with his next touch, stroking the ball into the far corner with the outside of his right boot.
The galling thing for Guardiola, who at one point found comfort squatting on the edge of his technical area in a black puffer coat and brogues, was that City passed up an opportunity seconds earlier. City succinctly shifted the ball from left to right but Raheem Sterling undercooked the key pass after spying Kyle Walker on the overlap.
Sterling was guilty of missing a decent opening too, blasting over after cutting inside Che Adams but Southampton had Fraser Forster to thank for preventing City from levelling. Phil Foden sent in a teasing cross from the left flank, which Romain Perraud failed to clear and just as it seemed Sterling would tap-in – the Southampton supporters in the Chapel Stand behind the goal sighed in unison as the ball found its way towards the back post – a sprawling Forster saved with his legs.
Guardiola could afford a wry smile as he headed down the tunnel at the interval and the scoreline would have been worse had Armando Broja been onside when the commanding Oriol Romeu, who was given his Barcelona debut by Guardiola, played the striker in on goal with a wondrous through ball on 23 minutos. Broja crept behind Walker but had strayed a shade offside.
The home support were on their feet again five minutes later in anticipation of a penalty when the referee, Simon Hooper, put his whistle to his mouth after Ederson brushed with Broja as the striker surged on to Adams’s pass in the box, only to award City a free-kick for an offside.
Southampton had no desire to sit on their lead and within a couple of minutes of the restart Ederson pushed a Jan Bednarek header from a James Ward-Prowse corner to safety.
City were zipping the ball around, with Jack Grealish, operating down the middle as a false nine, drawing the odd foul but the hosts, not for the first time, came closest to doubling their advantage before City began to dissect their opponent. Another Ward-Prowse corner caused havoc in the City area and Broja nodded against a post from a yard out. Guardiola had seen enough and called for Gabriel Jesus, who replaced Sterling.
Rodri earlier curled a shot on the roof of the Southampton goal and Foden saw a volleyed effort repelled by Forster as City tried to ratchet through the gears.
Then came the equaliser that swung momentum in City’s favour. De Bruyne flighted a free-kick towards the back post, where there was a scattering of dark blue shirts and Laporte powered in a header. Guardiola clenched both fists and embraced his assistant, Juanma Lillo.
Desde allí, City refused to give Southampton their ball back and the visitors piled forward. De Bruyne could only bite his lip in frustration after curling a shot against the woodwork and Guardiola had his hands on his head when Jesus headed against a post with the goal gaping.
City would not go quietly but Southampton held on through six minutes of second-half stoppage time.