Raheem Sterling has now contributed to 25 goals in 19 Premier League appearances at the Etihad since the start of last season
Manchester City cruised to victory over a sorry Southampton side to return to the top of the Premier League.
City took just six minutes to open the scoring as Wesley Hoedt smashed an attempted clearance of Leroy Sane's cross into his own net, before Sergio Aguero doubled their lead by tapping in Raheem Sterling's cross.
David Silva slammed home their third from Sane's flick-on after 18 minutes but Danny Ings did pull one back from the spot after Ederson brought him down in the area.
Sterling then netted either side of the break to complete an impressive personal performance, while Sane added a late sixth to cap off a fine afternoon for Pep Guardiola's men.
Both of the England forward's goals were assisted by Aguero, as the Argentine first crossed for Sterling to stroke in, before a slide-rule pass enabled the 23-year-old to finish emphatically.
Sane's goal came deep into injury time, firing past Alex McCarthy following a lightning counter-attack with Southampton legs tiring.
Guardiola's side have now won eight of their past nine matches across all competitions, although Ings' penalty was the first league goal they have conceded in six games.
Liverpool had moved above City after their draw with Arsenal on Saturday evening but the Reds held on to top spot for less than 24 hours.
Meanwhile, Saints are now seven Premier League games without a victory and lie 16th.
City's thumping win marked the 12th time that Guardiola's side have scored five or more goals in a single Premier League game since the Spaniard arrived at the club - no other team has done so on more than six occasions in the same timeframe.
And they threatened from the off, as Southampton had already been warned of their hosts' attacking quality several times, before Hoedt's attempted clearance ended up in his own net.
Aguero had already spurned one good chance before he turned in Sterling's cross for his 150th Premier League goal, after the England forward and Bernardo Silva linked up classily.
David Silva then added his side's third in the 18th minute, his powerful volley from Sane's flick-on leaving McCarthy helpless, but before then the Blues had seen a number of dangerous attacks break down.
The home side eased off after this early blitz, which saw them enjoy 81% of the possession in the opening 20 minutes, with a fifth straight league win over Southampton already in the bag.
Livewire Sterling shows his class
Raheem Sterling has now contributed to 11 goals in nine Premier League outings this term
Ings' penalty seemed to reignite the hosts' appetite for goals, as City began to push again, in large through the excellent Sterling.
And it was the ex-Liverpool winger who netted their fourth, stroking in at the second attempt, after initially miss-controlling Aguero's pass.
After being heavily involved in all three of their opening goals, Sterling's effort was richly deserved.
The England man was lively throughout, and although he could have done better with several half-chances, he illustrated his clinical side by powering in his 50th goal for the club on 67 minutes.
Having earlier set up Aguero's tap-in, Sterling again turned provider late on, as it was from his pass that Sane netted City's sixth.
The German's strike took his club's goal tally to 33 after the opening 11 Premier League games, meaning they are well on their way to matching last season's record-breaking tally of 106, although they had already netted 38 by this stage in 2017-18.
Saints blown away
Few would have given Saints much of a chance coming into this match, given the fact they were winless in their last eight visits to the Etihad prior to Sunday, and that proved to be the case.
Guardiola's side were ruthless, punishing nearly every goalscoring opportunity in the opening stages.
And although Ings' fifth goal of the season did provide them with a potential way back into the game, they never looked like producing any sort of comeback.
Chances were few and far between for Mark Hughes' side, although Ings did draw a good save from Ederson after the Brazilian had fumbled a powerful James Ward-Prowse strike.
And City's goalkeeper also had to be alert shortly after, getting down low to keep out Ings' near-post header.
But they failed to mount a sustained period of pressure, and it was the home side that looked more likely to score throughout the second half, as the Saints' search for a second Premier League victory of the season goes on.
-- Courtesy of BBC Sport