The 31-year-old British Lion scored Wales's only try of the game in the 45-10 mauling after a below-par Welsh performance and says his side need to blow away the cobwebs, starting with Sunday's visit from Ireland.
"Ireland are rated as the second best side in the world, so they are going to be just as tough as New Zealand to beat," said Williams, who will win his sixty-fifth cap when he runs out on Sunday. "We were disappointed with our performance against the All Blacks.
"As good as they are, we thought we could give them a tough game, but it wasn't to be. We weren't scared or in awe of them, they are just a class side who strangled us for the first twenty minutes and we went out of the game too early.
"We didn't really click as a team or hit top form during the Invesco Perpetual Series and that is something we have addressed. We know the Irish boys really well from the Magners League, probably as well as any of the other sides.
"There is always huge pressure on a Wales side playing at home; it's like playing under a microscope, especially when the RBS Six Nations is on and this is our only game before our last game in Cardiff against England. Everyone is going to be building this one up, but this is a competition they really want to win."
Ireland have named a strong side with Llanelli Scarlets flanker and captain Simon Easterby named to face Wales, alongside Munster's pair of Dennis Leamy and David Wallace.
"Ireland's strength in depth is frightening," said Williams. "They have got six players who could come into the back row and do just as good a job, guys like Dennis Leamy are playing some top rugby and Neil Best hasn't even made the side, yet has played some great rugby this year.
"Whoever plays in the Wales back-row will face a tough job."