Dane Haylett-Petty admits a sheer lack of "heart" was the reason why the Wallabies produced one of their worst halves of rugby in recent memory in Salta - then backed it up with one of their best.
Haylett-Petty was one of the stars of the show in Sunday's (NZT) stirring 45-34 comeback win over Argentina, scoring two of the team's five tries in the second stanza at Estadio Padre Ernesto Martearena.
His first-half performance was scratchy but given the nature of the match, he certainly wasn't alone.
The 29-year-old couldn't get his head around how Australia could go from woeful to wonderful so quickly.
"That's something we need to go back and look at and there's a big lesson there for us," Haylett-Petty said.
"Obviously the second half is how we want to play and the first half is not how we want to play.
"It wasn't so much technical, it was just heart probably.
"We knew we had to respond, we knew this was an important game, we've been under a bit of pressure as a team and I think the boys came out and responded."
Haylett-Petty barely trained in the lead-up to the match and was bed-ridden with a nasty virus and stomach cramps less than 24 hours before kick-off.
He has hit a rich vein of form since moving from the wing to his preferred position of fullback, which should now remain his permanent home at Test level - particularly with Israel Folau excelling in his floating role across the backline.
"He didn't train on Friday, he's been quite ill... but in the end he was going so good I couldn't take him off," coach Michael Cheika said.
"I feel sorry for the guys who didn't get a run but when players are on a roll like that, you don't want to be making any changes if you can avoid it.
"He's done well and in the same breath too, Izzy has really managed that roving role he's got out there excellently.
"Sometimes he's on the edge, sometimes he's at the back, sometimes he's on the frontline.
"Dane's counter-attacking well. That stuff's good but I just can't get the picture of that first half out of my head, unfortunately."