His nadir came in a poor performance in that 20-6 semifinal defeat in which his first act was to kick the ball out on the full.
Cooper's attacking talents are undeniable if he is in the zone, but there is a fragility about him that will make him a target once again for the All Blacks on Saturday.
Another failure after his selection ahead of Bernard Foley could seriously damage his confidence.
It is one more talking point in a build-up to a test which isn't short of them - the selection of David Pocock on the Wallabies bench after his standout game in Sydney is another - and if there is a deja vu element to Cooper's selection there is too in that of Victor Vito for the All Blacks, a man seemingly out of the frame since his last start for the team in Scotland last November.
As Hansen and the All Blacks face up to last weekend's defeat in Sydney, the potential loss of the Bledisloe Cup, and a groundswell of opinion - led with some delight by the Northern Hemisphere media - that the team's dynasty is danger of being ruined should they lose again, the home side will have to make do without any specialist lock cover.
Instead of Luke Romano being named back-up to Brodie Retallick and Sam Whitelock, Jerome Kaino has been named as the extra forward with the potential to cover lock, a final tweak in the final test before the Cup.
"The World Cup year brings its wee quirks," Hansen said.
"You roll the dice but ... those little quirks won't prevent us from winning the test match if we turn up with the right attitude.
"If we bring the best of what we've got then we force Australia to bring their best and while everyone is saying we're under pressure, I think Australia now have put themselves in a place where people have got high expectations of them. And with that comes pressure, too.
"It's one of those great test matches, we're going to find out who's got the steel and who hasn't."
After a frantic start in Sydney, the All Blacks appeared to take control only to lose their way.
They're confident that won't happen again, but there is genuine interest building as to what their response will be.
"There's got to be a response," said Hansen. "Because if we don't respond to it we're going to run second and we don't like doing that much. Whether the response is good enough we'll wait and see, but there will definitely be some sort of response. There's already been one this week - you can feel there's a bit more edge."
