Pep Guardiola kept his Manchester City players locked in their dressing-room for nearly an hour after their winless run stretched to five games.
Guardiola did not emerge from the home dressing-room until 50 minutes after the final whistle, determined to deliver some home truths in his post-match inquest.
John Stones gifted Southampton the opener after 27 minutes, Nathan Redmond seizing on his poor back-pass to open the scoring for the visitors.
Substitute Kelechi Iheanacho earned a point for City with a 54th-minute equaliser, enough to keep them top of the Premier League on goal difference.
But Guardiola’s decision to keep his players confined to the dressing-room for so long showed how angry he was, even if he did try to play it down afterwards.
“The red wine was good and I took a little bit longer,” joked Guardiola.
“We were together, we spoke, but nothing special. We spoke about the situation.
“I was football player so I know this can happen. You’re able to win 10 times in a row and after you’re not able to win five times.
“You have to accept that, but I have to discover the reason why and I’m going to fight for that.”
Guardiola refused to blame Stones for City’s failure to win, just as he absolved keeper Claudio Bravo when he was sent off in last week’s 4-0 Champions League defeat at Barcelona.
“Today with John and on Wednesday with Claudio, that is not the reason,” said Guardiola.
“Against Everton we missed two penalties, we played amazing and didn’t win.
“It’s something more and about the team and how how you react.
“It’s part of the process of how we react and how people react to a new manager here, but football is complicated.
“We didn’t have 90 bad, bad minutes, but when we’re not perfect, we concede a lot.”
Saints scorer Redmond said: “We knew they’d give us chances because they only play with three at the back.
“We can take the positives. We’ve come away with a point, but with our mentality in the squad, we want all three points.
“Even if we draw, we’re frustrated that we didn’t get all three points. But we’ll take the point and keep going.”
City midfielder Kevin de Bruyne came off at half-time with a calf injury and is set to miss Wednesday’s EFL Cup tie at arch-rivals Manchester United.