Hugo Ekitike has scored another winning goal for Liverpool, but this time his joy was short-lived. You could see it dawn on him in real time that he was about to get a second yellow card for removing his jersey, as Anfield abruptly stopped celebrating and started thrumming with disbelieving murmurs.
The mood on the way out of the stadium was broadly jovial. It was clearly a stupid thing to do, but you can generally be cut a little more slack when you've just fired your team into the next round of the cup.
Unfortunately for Ekitike, the standards in the dressing room are more exacting than that. Andy Robertson has already grimly noted that the Frenchman "won't be doing that again", while Arne Slot pulled no punches in his post-match interview either.
The Liverpool boss branded Ekitike's actions "needless" and "stupid". He has clearly been left in no doubt that his spur-of-the-moment mistake has gone down like a lead balloon among colleagues.
But just to further underline that point, a formal punishment from the club is expected. According to the Mail, Ekitike is likely to be docked two weeks' wages.
That's not far off a quarter of the salary Liverpool has paid Ekitike to date. While he still probably won't have to worry about the heating bill, the fine would be symbolically powerful.
In fairness to the striker, he issued a public apology shortly after full-time. Though he has felt the full force of the champions' standards, he will certainly be able to find forgiveness quickly.
If anything, the incident has probably endeared Ekitike to some fans even more. Not everyone would get swept up in the joy of a third-round Carabao Cup encounter, but the 23-year-old comes out to prove himself every time that he dons the Liverpool jersey (or in this case, takes it off).
And you can certainly understand him wanting to make his point. He is battling against Alexander Isak, one of the best strikers in the world, who also found the net against Southampton in his first domestic start for Liverpool.
The great irony, of course, is that Isak will likely now get the start against Crystal Palace at the weekend. Ekitike would almost certainly have been given another chance to impress, but will now have to watch from the sidelines as the record signing stakes his own claim.
But the season is long, and both will get their opportunities. Before the incident, Ekitike could hardly have done any more to give Slot a decision to make, scoring five goals in his first eight games.
It speaks to the impression he has made that he will be so missed against Palace. He would have been among the first names on the team-sheet, having earned lofty comparisons to the likes of Fernando Torres in his short time at Anfield.
That's not to say that Liverpool doesn't have the depth to get past the London side without Ekitike. The Community Shield proved that it will be a tough game, and Oliver Glasner is remarkably now 17 games unbeaten, but there is room for optimism that the Reds can make it eight wins out of eight to start the campaign.
If they keep up this kind of form, then even Slot will be able to laugh about Ekitike's mistake come the end of the season. But with a fine seemingly on its way, it has been made very clear to the forward that this is no laughing matter.