Spurs go to Chelsea on Sunday on the back of defeat at Bournemouth in midweek.
"For me the disappointment last night, there was a repeat of cycle of us going into games, starting well enough but then allowing the opposition to get a grip on it by either conceding a sloppy goal - like we did last night - or not taking our opportunities," he said.
"We need to break that cycle, irrespective of where we are at the moment. We know we are really thin on the ground in terms of squad numbers. We know there is not a lot of opportunity to rotate and rest players. We paid the price with Benny (Davies) last night.
"Those are known things. What also is known is we repeatedly shot ourselves in the foot in games like last night and we need to change that."
Postecoglou also rejected criticism of focusing on adding young players over the summer.
"We needed to do that because it was a team that was coming towards the end of its cycle, and we were rebuilding not just the squad but the playing style, and you couldn't replace experience with experience because that is not a rebuild," he said.
"The decisions we made around signing young players are the right decisions for this club for where we are at right now, and they will bear fruit."
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