The Rangers legend has recently expressed dissatisfaction with Tottenham Hotspur, Postecoglou’s current club.
The Australian took over at the Premier League heavyweights in the summer of 2023, having won the treble with the Hoops.
His high-octane, high-pressing, all-out-attacking style of play in the Scottish Premiership won him a move to Tottenham.
However, his approach to the game has proven ineffective on numerous times in England’s top division.
Souness has called it ‘naïve’ rather than daring.
“When I think of Ange Postecoglou, I go back to that game against Chelsea where they got two players sent off and he still had them playing right up to the halfway line,” the 71-year-old told Simon Jordan and Troy Deeney on William Hill’s Three Up Front podcast.
“The only time you can do that is when you’ve got 11 players on the pitch and the ball is constantly under pressure.
“The minute someone can get their head up, you’re in trouble.
“They could have conceded four or five more goals that game – I thought that was naïve.
“It’s naïve to talk like that and say that the more open the game is, the better it is.
“If they’d lost that game seven or eight goals to two, you’ve lost the players as a manager. He wasn’t brave that day, they got lucky.
“He’s walked into Tottenham without bringing any of his own staff, is he so naïve as to think he can trust any of the coaching staff he’s inherited not to go to the chairman with their tittle-tattle?
“I would not take a job and think I can just walk into it – it’s madness – you need to go in with people you trust because being a manager is lonely.”
Souness questioned the team’s leadership on the pitch after Spurs’ most recent game, a 3-2 loss against Brighton in which they imploded to give up a two-goal lead.
He added: “The Tottenham players should have known better. You learn it at school – when you’re 2-0 up the next goal is vital.
“If you concede, the momentum is suddenly with the opposition but if you go to 3-0 up, the game is over.
