McKenzie kept his side on the field at half-time of their 28-8 defeat to South Africa at Newlands, their biggest ever margin of defeat in Cape Town, as he gave them a very public dressing down.
Having trailed 23-3 at the break, they did improve in the second half but at no point looked like mounting a significant fightback.
"You can have all the ideas you like about how the game will pan out but you have to make adjustments on the field," McKenzie told reporters.
"We were probably a bit too conservative for too long, but as soon as we ran at them the penalties started coming our way.
"There are parts of our game that are improving, we have been putting in the effort, I can't fault that. But I feel like I say this every second week, there is a maturing aspect that we need to find."
Australia have lost four of their five Rugby Championship matches this season, their only respite a narrow 14-13 win over Argentina in Perth.
McKenzie does not believe that adds any extra significance to Saturday's final fling in Rosario.
"Every game is crucial. We don't sit there and value the games," he added.
"The good teams do well for longer periods of time and grab their moments, we are not grabbing our moments. Test matches are about pressure and right now we lack composure in key moments.
"As a coach you come across these periods of time, I've had it before with other teams. There is not one thing you can fix and it magically comes right, you have to fix a bunch of things and that is what we are trying to do.
"We had opportunities to put pressure on South Africa but lost out through poor execution. That's where we are at the moment, all we can do is keep plugging away."
Argentina showed enough at home against South Africa and New Zealand to suggest they will be a big test for Australia, something McKenzie acknowledges.
"Argentina is a tough place to play, but that's alright, we will dust ourselves off and get over there. I think we have made a fair bit of progress, it has just not showed itself in the scoreboard."