There are two things hitting home with Billy Vunipola as he approaches the third Test in Sydney on Saturday. He is finally getting in tune with coach Eddie Jones's notion that he can be the best No. 8 in the world and he knows he must not repeat the sort of clanger he made on the stroke of half-time last weekend that led to one of the most astonishing rearguard defensive performances ever produced by an England side.
Vunipola is a player transformed under Jones: more dynamic, more assured, more at ease with himself and who he is, a Tongan, Sydney-born, Wales and England-shaped personality, who is beginning to realise his potential on the world stage. It would help that development if the 23-year-old could avoid another momentary lapse of concentration like the one when he hoofed the ball into touch in the belief that the clock had run down on the first half. Instead there were two seconds left and the Wallabies went for the jugular, subjecting England to a 22-phase attack that lasted almost three minutes.
It will go down as a defining moment in the growing history of this Jones team, a goal-line stand that ranks alongside that of the 13 men who held out for victory against the All Blacks in Wellington in 2003. That sort of lung-rasping resistance becomes something to draw on in hard times, a reference point. And it all came from a cock-up.
"There was no one else to blame but myself," Vunipola said. "I thought the time was up but obviously it wasn't. It was never my intention to make the boys work like that, but it did give us a lot of confidence going into half-time that we could hold our line. The only thing going through my head was the thought of getting up and tackling someone, to not let them score.
"Once you've made a decision it is important that you move on quickly. We have that mindset as a team. We back each other up. The boys certainly backed me up from that decision. It was my error. We had packed down for a scrum and I saw that there were 20 seconds left. I thought to myself that a scrum doesn't last 20 seconds, so I held the ball in but I didn't actually look up at the clock It wasn't a smart decision.
"No one gave me a rollicking. We're too nice to each other now. The boys were like: 'Don't worry, we'll do it for you.' My poor brother, Mako, was rushing around just as much as me to make sure that the mistake didn't fall back on me."
Vunipola showed prominently throughout the second Test, a far more dominant figure than he was during those hang-dog World Cup days when he trudged around and made little impact. Jones has drawn the best from him, by praise rather than coercion, emphasising time and again that greatness is within his grasp. For that to happen, the Saracen has to graft and, more tellingly, he has to believe.
"Eddie wants me to be this player that I don't even see myself," Vunipola said. "He wants me to be challenging the best No. 8s in the world. Now that he's told me, I think why not? That's my goal, that's what I'm working towards. Eddie has been a great influence on me."
That much is evident in the marked difference in Vunipola's outlook, no longer the puppy-fat kid, now an adult taking responsibility. He has already set his goals for next season, pledging to keep his weight constant rather than let it balloon as it normally does. As one who was born in Sydney and lived here until he was six, he has not met up with his extended family on this trip for fear of getting distracted.
"There's actually a whole bunch of my family here but the focus is on Australia not in meeting aunties and the like who might want to feed me up," he said.
Vunipola thrives on the carrot rather than the stick. He was not as inspired as some of his team-mates by the use of the Man in the Glass poem used by defence coach Paul Gustard last week, but he has responded to the feel-good vibes in the group.
"The poem? To be honest with you I'm not really big on stuff like that," he said. "But Gussie is very good with intricate words and he makes people feel good about themselves and that's right for me."
England have continued training at full-bore this week as they look to complete the clean sweep against Australia for what would be a milestone moment.
"There has been no let-up because we have given ourselves no other choice," Vunipola said. "We said at the start of the tour that we wanted to win 3-0. We made that promise to each other and we can't break it now."