Anything was possible with the pairing of Anton Lienert-Brown and Jack Goodhue, Williams said.
"For us as midfielders we pride ourselves on trying to be world-class whoever is in that 12 or 13 jersey or whoever is playing at the time so this weekend will be no different.
Ireland had a strong midfield combination and the All Blacks knew they were going to be challenged in that area.
"They are always a threat. They were the No 1 team in the world a couple of months ago, or just before the tournament started, so we're under no illusions the threat that they will pose but for us it's about bringing the All Blacks' A game.
"That's what we're about and I think for myself being involved with this team, if we get our mental prep right and come with that attitude and intent then we're going to be hard to stop so that's what we're going to be looking at doing," he said.
"At this tournament anything is possible; teams rise, teams fall but I guess it is the team that can be in that moment and breaks the challenge the best that will come out on top. This week's no different."
While there was pressure from outside the team to perform, inside the unit the quality of players was really high and expectations were always going to be high because they challenged themselves and each other to play good footy because if you didn't someone else would take your spot.
"On top of that the environment we try to have is: team first, selfless, do your best and I think all of that mixed in together you get what you get and I guess a pretty good footy team."
The biggest stages could provide the biggest memories and the All Blacks were going to try and create a positive memory this weekend, he said.
Hooker Codie Taylor, who won the hooking berth ahead of Dane Coles, said he was grateful for the opportunity and he knew he had a role to play and was looking forward to the challenge ahead.
"You dream of these moments as a kid when you're watching World Cups. I remember watching in 2011 and there's a few boys still running round who are going to be in Saturday's game and it's real special to be part of such an awesome team and an honour to represent your country," he said.
Taylor talked about his relationship with fellow Horowhenua All Black, and hooker, Coles. He said he first met him when Coles went up to Levin to attend Taylor's 18th birthday at a Sevens tournament in which Taylor was playing with a few of Coles' mates.
"That was the first time I had a good yarn with Colesy and I suppose I went away for a few years and then managed to join the team with him. He's still the same guy, still a humble Kapiti boy who goes hard on the field and he's not afraid to walk towards anything," he said.
Coles had been through a lot to recover from his recent injuries and deserved every right to get out on the field on Saturday.
"If I can perform even better than what he has in the past then I'll be doing this team a great justice," Taylor said.