The return of Erling Haaland sparked Manchester City to dominant win that cut the gap at the top of the Premier League to five points.
After bottom the table Southampton, who knocked City out of the Carabao Cup in January, had started well, Haaland nodded home a Kevin De Bruyne cross just before half-time to open the scoring.
Jack Grealish fired in at the second attempt to double the lead in the second half, before Haaland acrobatically volleyed a 30th league goal of the season's from Grealish's cross.
Sekou Mara pulled one back for Saints, but substitute Julian Alvarez, on for Haaland, immediately restored the three goal advantage.
Here are the game's talking points.
1. Saints are alive, but wasteful
There were signs of just what Southampton want to be doing in the first half, when the lively Kamaldeen Sulemana was their best hope of worrying City and indeed their most likely chance of a goal.
One lightning break got St Mary's on its feet before the 21-year-old - a club record signing from Rennes in January - just seemed to run out of road to move into and room to hurt City, for whom the consistently impressive Nathan Ake had got back well.
Indeed, much of Southampton's first half endeavour seemed to be summed up by Sulemana.
The spirit was willing, but the execution weak.
2. The man for the moments
Regardless of how poorly Liverpool are playing, there was a sense that if Haaland had to miss one City game through injury in this title run-in then the Reds at home wasn't a bad one.
City crave control in those matches, and so switching to a roving, more mobile attacking output as opposed to their regulation No.9 allowed them to swarm all over the pitch and dominate the ball, eventually suffocating the hapless visitors.
Here they were always likely to have the vast majority of possession, but it was going to come down to taking chances and, crucially, scoring that opening goal that would break Southampton's spirit.
Haaland did that just before the break, moments after another Sulemana effort which had drifted wide of goal.
He'd barely touched the ball before that, but then he hadn't needed to.
In the second half came a stunning acrobatic effort which then took his tally to 30 league goals for the season, making him the first City player to achieve that feat since Franny Lee in 1972.
More will come soon.
3. Kevin the king of the creators
That first Haaland goal had been created, of course, by De Bruyne, with the Belgian clocking up his 100th Premier League assist when his Norwegian team-mate nodded home his cross.
He's the fifth man to bring up the number, but the one who has done it the quickest time, reaching his century in 237 games - some 56 quicker than closest challenger Cesc Fabregas. FIFTY SIX.
A consequence of playing in such a dominant team? Of course, but also of his outstanding quality.
There have been few, if any, better creative midfielders in the division's history.
4. Can Grealish keep adding goals?
The good news for Grealish is that the more decisive impacts he makes on matches the less he'll hear people going on about his £100m price tag, and he's going about that challenge the right way.
After his goal and *that* excellent defensive work against Liverpool last week came another strike here, a fifth of the season and basically the goal that confirmed City's victory, as there was no way back for the Saints after that.
Grealish himself admitted that he felt on the fringes of City's Premier League title win last season, but he's every chance of being a key contributor to this one.
5. Going first pays off
So, over to Arsenal then.
Despite their defeat here in the Carabao Cup earlier this season there was never any real sense that City were going to drop points, and so the whole idea of them 'going first' before Arsenal go to Anfield tomorrow is really just the knowledge that a win would cut the gap to five.
Given the hype around the game at Liverpool - hype there are somewhat creating themselves - then how Arsenal respond will frame the rest of the title race.
City could do nothing more than send this message. Now they wait.
