Gavin Bazunu, Southampton’s keeper, kept his side in the game for 20 minutes with fine saves but was powerless against the individual brilliance of Joao Cancelo who opened the scoring for the hosts after dancing past the defence.
Just 12 minutes later Kevin de Bruyne set up Phil Foden for City’s second goal to practically seal the match before halftime. Southampton, however, managed to get some efforts in on the Man City goal before the break to signal some intent.
It took the hosts just three minutes after halftime to nip those thoughts in the bud as Rodri beat the defence with an over-the-top ball which Riyad Mahrez volleyed into the back of the net.
Erling Haaland, who missed several chances earlier, also managed to get on the scoresheet in the 64th minute to take his goal tally of the Premier League season to 15.
The win also takes City top of the table once again with 23 points from 9 matches.
Meanwhile, in other contests, a par Tottenham side managed to overcome Brighton 1-0 thanks to Harry Kane’s first-half strike while Chelsea beat Wolves 3-0 to climb into the Champions League places.
Leicester City’s troubles deepened with a 2-1 loss to Bournemouth while Newcastle United smashed five past Brentford during the 5-1 win.