The pressure of finals and knockout matches is such that clear thinking and the taking of opportunities are what generally make the difference - think Elliot Dixon's stunning run to the line despite being outnumbered by the Hurricanes' defence, or Banks' superb late dropped goal to push the Highlanders' advantage to seven points.
They are qualities which Barrett has generally had in abundance for the All Blacks, especially in his role as super sub extraordinaire, where his acceleration and ball skills can make defences look ridiculous.
For whatever reason, he didn't fire in his last match for the Hurricanes but on the eve of the All Blacks' departure for England for his first experience of the global tournament, Barrett is excited about not only the opportunity he is about to get butalso the way his team are likelyto play.
Coach Steve Hansen, who will put the finishing touches on the preparations in an Auckland camp today and tomorrow, has put the onus on his team to attack and in Barrett they have a player who likes to do just that.
"I like to attack with ball in hand," he said. "I like to back my skills. That's just the game I've played all my life ... when things aren't going my way I'm probably not being positive enough."
For Barrett, who will vie with Colin Slade as back-up to Dan Carter in the No10 jersey, his naming in the World Cup squad is a dream fulfilled - not only his, but also his family's.
He was at home at his parents' Taranaki farm when he got the call and the champagne was duly opened by mother Robyn and father Kevin, who will travel to Britain to support him.
Rugby has played an important role in the lives of the Barretts. Father Kevin played more than 160 games for Taranaki and brothers Kane, Scott, Blake and Jordie all play. Barrett also has three sisters, Jenna, Zara and Ella.
Asked what the game means to his family, Barrett said: "I remember growing up watching Dad playing for Taranaki. He played 169 games and I remember when Taranaki won the Shield off Auckland in '96 and the impact that had on a little town of New Plymouth and the province.
"It was pretty special and from those younger years I just wanted to wear that amber and black jersey. That was the pinnacle for me. Growing up and watching the All Blacks play, I just thought that was a dream. I didn't really believe it would happen ... I thought it was a little too far away for a Pungarehu kid."