Williams, all 5ft 8in of him, will be the smallest player on view at Westpac Stadium, where the British & Irish Lions must stand tall against an All Blacks side installed as favourites to clinch Test series glory following their victory in Christchurch last weekend.
The Wales wing, who has scored 24 tries in 29 Tests, is among seven new faces summoned by Lions head coach Sir Clive Woodward.
He will joined by centre Gavin Henson, hooker Steve Thompson, lock Donncha O'Callaghan and back-row trio Simon Easterby, Lewis Moody and Ryan Jones, while a reshaped back division sees positional moves for new skipper Gareth Thomas, Jonny Wilkinson, Josh Lewsey and Jason Robinson.
Williams' five-try display against Manawatu in midweek was worth the entrance fee alone, and with Wales Grand Slam colleagues Henson, Thomas and Dwayne Peel alongside him, there could be fireworks.
"I am just looking forward to it immensely," said 28-year-old Williams, of his Test debut in a Lions shirt.
"Size has been a concern in the past, but if you look at the likes of Jason Robinson, he is not much bigger than me and look what he's done in his career.
"Hopefully, I am an inspiration, especially if players like me can get these six-footers down, and tackle them and run around them."
His opposite number, Rico Gear, is one of those six-footers in question, but if enthusiasm and talent counts for anything, then Williams won't concede an inch.
"Being selected probably hasn't sunk in, and it is just an incredible feeling," he added.
"I am more excited than anything. I just want to go out there, and as long as I do a job I believe I can do and I don't let myself down, I will be a very happy man.
"I have worked hard on this tour, and I didn't let my head drop when I was left out of the first Test.
"I've trained and played with a smile on my face. I've kept working and I have been given a chance, for which I am really grateful. I want to go out there and enjoy myself."
Williams found himself tagged as the unfortunate 23rd-man last week, having not been used during the midweek victory over Southland and then missing out on Woodward's first Test 22.
Now he has got his chance though, Williams does not intend to disappoint.
"Clive has certainly got confidence in myself and Jason. He knows Jason's capabilities, and hopefully, I can do the same as well," he added.
"I thrive on games like this, to be honest. The bigger the game, the more I enjoy it.
"It means you have got to compete against some of the best players in the world, and what better game to perform and play well in than against probably the best international team in the world at the moment?
"In New Zealand, they seem to have big players who are quick. But with the likes of Jason Robinson and French wing Christophe Dominici, they've proved in the past that size doesn't matter.
"I will certainly be going out on Saturday to try and prove that. I am on a high at the moment.
"It is a massive test of my ability, and I am going to be slightly nervous, but I think it is excitement rather than nerves, and if I could play the game now, I would."