Postecoglou has praised his side's collective defending
Ange Postecoglou says his tactics make life difficult for his defenders but the aggressive approach is the foundation of Celtic's success.
The Scottish Premiership leaders have gone five matches without conceding.
First-choice defenders Greg Taylor and Cameron Carter-Vickers returned as Celtic saw off Dundee United 2-0.
"Our defensive work since the World Cup break has been outstanding. It gives us the foundation to play our football," said the Celtic manager.
"If we are working really hard defensively, collectively, and are really organised and disciplined, it suffocates the opposition.
"It doesn't give them time to breathe and allows us to wear teams down, break them down one way or another. That's through everyone being committed to it.
"It is a very important part of our game. We wouldn't be the attacking side we are and score the goals we do if we didn't have the defensive framework to fall back on."
The Australian acknowledges that his front-foot, 'pressing' philosophy means his defenders must be able to cope with being left exposed with the team so often closing the opposition down high up the pitch.
Postecoglou says it means only a certain type of defender can cope with being in his team.
"It's not easy to defend in our team. We are constantly pushing the line, but we want to be aggressive," he said.
"It means a lot of one-on-one defending, one player defending without cover.
"You need to embrace that as a defender and be willing to put yourself on the line."
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