He looked more at home in the second half with fellow Reds campaigner, halfback Will Genia, replacing Nic White.
He didn't want to use excuses about a new coach or injured players to explain their dip in form.
"We can't keep using excuses. We've run out of excuses as a team in terms of how we go about each week.
"We've just got to put it down to hard work, sticking together as a team, backing our coach, backing our players and we've got to strive for more success."
Cooper said there was a challenge issued to each player to improve on one thing each heading into the Argentine game, which they hoped would collectively make a difference.
"You have to look at yourself and find one thing in your game that you can work on, that you can contribute to the team, that will speed up the process of us improving as a team.
"We'll get there. It's all in due time but I urge everyone, it's not going to happen overnight.
"It's something that we've got to continue to be upbeat about but we've got to know that it's a tough process and it's something that will come but, right now, it's just not happening."
Cooper used Queensland's Super Rugby revival under McKenzie as proof that the coach was the right man for the job.
"He's got the (Australian) team with two weeks' preparation and he's got to try his best to mould us all together into a team that people want to watch and want to support.
"We've got to stick with him as players and, like I said, it's not going to happen overnight but I've got full confidence that we have the playing group and the coaching staff to turn things around."
Australia held on for a one-point win over the Pumas in Perth earlier this month and Cooper said it would be a real battle for his team.
"We know it's going to be tough.
"They're a good side. They have improved heaps being in the Rugby Championship.
"We're not going to go there thinking we're going to roll them.
"We cannot afford to think like that, especially with the way they're playing football."
- AAP
