The 24-year-old Welsh fullback will go into the Lang Park clash on the crest of a wave after outstanding performances in the warm-up games, where he has landed 22 of his 23 attempted goal kicks, and confident he can make a decisive contribution.
"Every kick in an international match is crucial," he said. "We all know how games are won and lost in international rugby by fine margins and, more often than not, in big games kicks are deciding the outcome."
Halfpenny proved his enormous potential as a kicker when he was joint leading points scorer in the 2012 Six Nations and was voted as Player of the Tournament for the 2013 edition earlier this year.
He has said he owes his success to the guidance of Lions' kicking coach and fellow Welshman Neil Jenkins, whose placekicking was crucial to the Lions' last triumphant tour in South Africa in 1997.
"Jenks is massive for us as kickers," said Halfpenny. "For me, he's been huge growing up. Since the academy, I've come right through with him to senior level.
"He's been massive in every game and preparation for every game.
"We speak about his memories in the car after kicking sessions now and again, but he's just focused on getting us kickers prepared for this Saturday.
"He was the best in the world in his day. For me, I couldn't think of anyone better to have bringing on the tee and giving me the pointers just before the kick. He's been massive for me in terms of my progression through the years.
"But Jenks can only do so much. It's up to us to go out and perform. He's huge for preparing mentally and technically and I'm focused on trying to do the best I can."
Once seen as a kicker only to be wheeled out for the 50-metre plus shots beyond the range of his flyhalf team mates, Halfpenny has developed into the Lions' first choice.
Unsurprisingly, he puts much of his success down to years of dedicated practice.
"I think the hard work you do throughout the week, the hard work that's gone in throughout the years - all those years, since I was a little kid practicing - is all for moments like this," he said.
"You watch Lions tours growing up. You're watching them as a kid and thinking 'I'd love to be kicking for the Lions, putting the Lions jersey on'.
"It's all dreams. To be actually selected to play in a test is just a dream come true, really.
"I never thought about it, growing up. It's just ... mad!"
Halfpenny said he is so busy doing his job during a game that he does not count his successful kicks.
"The boys joke about 'have I missed?' and that, but for me it's just focusing on every kick as it comes.
"In a game you get asked at the end, how many? For me, I don't know how many I've kicked until I get told.
"You're so focused on the next kick. Once you've kicked one, that's gone and you're focusing on the next one - and that's the one that counts, whether you've missed or put it over the one before.
"The next one is the important one that you're concentrating on."
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