Saints came to play football and played their part in a match that was packed with goals, incidents and talking points.
The victory restores City's 14-point lead at the top with nine games remaining.
Southampton started brightly, restricting City’s possession with a high press, closing down and doubling up whenever possible.
But if the intention was emulating Manchester United’s effective tactics from Sunday, the hard work was undone in City’s first attack on 14 minutes.
Ruben Dias spotted Oleks Zinchenko’s run down the left and his long ball was controlled by the Ukrainian and his low cross into the box found Phil Foden whose low shot was saved by Alex McCarthy and Kevin De Bruyne followed up with a shot that went in off the underside of the bar.
It was City’s first coherent move of the game and had taken 14 minutes, but nobody was complaining.
The lead lasted just 10 minutes – referee Jon Moss believed Aymeric Laporte had pulled back Jannik Vestergaard and awarded a penalty that James Ward-Prowse converted.
On the half-hour Saints keeper McCarthy appeared to bring down Foden as the youngster profited from his error but the referee wasn’t as generous this time and VAR backed him up.
Foden’s honesty may have cost him, while Vestergaard had gone down as though poleaxed – one penalty give, one not. Baffling.
Saints were playing well and Ward-Prowse again went close with a viciously dipping long range shot that Ederson did well to push over.
But if the City players felt they’d been hard done to with the penalty decisions, justice was done on 40 minutes with a Riyad Mahrez special as Che Adams played a poor pass across the pitch that Mahrez intercepted, moved to the edge of the box, dropped a shoulder, and then curled a low shot into the bottom left corner from 18 yards.
And in first-half added time, it got even better with Mahrez again wreaking havoc as he drifted into the box, twisting this way and that before stroking a low drive against the foot of the post and Ilkay Gundogan fired home the rebound to make it 3-1.
Within the first 15 minutes of the second period there had been three more goals in this pulsating match.
First Mahrez again tormented the Saints’ defence before curling a low shot home from 15 yards on 55 minutes.
Then some untidy defending allowed Che Adams to pull one back a minute later, before some excellent play by Foden allowed De Bruyne to collect the ball and ghost into the box to drill a low shot past McCarthy.
There were more chances at either end in the half-hour that remained, with bot sides unlucky not to add at least a couple of goals more to their tally.
It was that kind of evening!
Imagine being a full-back with Riyad Mahrez approaching.
You may have an idea of what’s coming but stopping him is another thing.
The Algerian has been called magical and unplayable in recent months and the Etihad Player of the Month is all that and more.
But another might be devastating – he is the stuff of nightmares for any opponent in his current form and he is getting better as the season enters it’s final couple of months.
Mesmeric stuff from a very gifted footballer.
Oleks Zinchenko doesn’t steal the headlines, score goals and rarely gets assists.
But he has become such an important player to this City side.
Steady, intelligent, and unassuming, he rarely misplaces a pass and just gets on with his job.
A full Etihad this evening would surely have given the Ukrainian a standing ovation for yet another polished performance.
WHAT IT MEANS
City go 14 points clear at the top of the Premier League but the three closest sides below all have one game in hand.
City travel to Fulham on Saturday evening, with an 8pm kick-off at Craven Cottage.
STAR MAN: MAHREZ
Two goals and an assist – not a bad hour’s work before being subbed!
“They were better than us in the first 25 minutes. We won because of the quality of Riyad and Kevin and Phil.
“The penalty (decision) was incredible. I don’t understand it. Maybe one day they will explain the rule around VAR.
“Hopefully one day they can explain why one is a penalty and the other isn’t. Jon the referee cannot see it but if the VAR can’t see it…
“In my time here, I've not criticised the refs. I just want it to be more clear.
“We won 5-2, if we lose 2-5, I don’t comment. It looks like an excuse. Sometimes we give arguments for what we see.
“Big compliment to my players, but the penalty is incredible.”.
City: Ederson, Walker, Zinchenko (Mendy 81), Laporte, Dias, Fernandinho (c), Gundogan, De Bruyne (Aguero 72), Foden, Bernardo, Mahrez (Torres 61)
Unused subs: Steffen, Stones, Sterling, Jesus, Rodrigo, Cancelo
Southampton: McCarthy, Stephens (Diallo 63), Bednarek, Vestergaard, Bertrand, Salisu, Armstrong (Watts 72), Ward-Prowse, Djenepo (Tella 45), Redmond, Adams.
Unused subs: Forster, Walker-Peters, Minamino, Ramsay, N'Lundulu, Ferry
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