The importance of Shaun Johnson getting through the rest of the World Cup unscathed was magnified after Thomas Leuluai was invalided out of the tournament, but Johnson's presence is needed by the Kiwis for reasons other than being a key playmaker.
The 23-year-old has emerged as a genuinely good goalkicker, except for one terrible miss against Papua New Guinea on Saturday morning when he hit the upright from in front of the posts (he calls it his Sonny Bill moment in reference to Williams' gaffe against Samoa when he slipped over the deadball line before dotting the ball down for a try).
He has landed 21 of 26 attempts at the World Cup for a success rate of 81 per cent. Admittedly many have been close to the sticks but he also landed sideline conversions against both France and Papua New Guinea and went a perfect eight from eight against France.
He's now posted 50 points at the tournament, easily the most of anyone at the World Cup - he's also scored two tries - and goalkicking could become critical in the knockout stages.
The Kiwis have others who are comfortable kicking for goal, including Issac Luke, Bryson Goodwin and Kevin Locke, but none in the sort of form Johnson is showing. It's quite some improvement from earlier in the year when he was under the spotlight after assuming the duties at the Warriors.
"With the kicking, it's a confidence thing," Johnson said. "I'm feeling comfortable doing it now. You saw how I started the season back home. It was all a bit new to me and having that season in the NRL kicking in front of those crowds has only done me good.
"I'm hitting the ball pretty sweet at the moment. I just hope it sticks around and it's there for the big games at the end of the tournament."
The Kiwis need Johnson to be around at the end of the month, particularly after Leuluai lasted less than five minutes against Papua New Guinea and is now out of the World Cup.
It was felt by both Leuluai and the coaching staff he needed to test his injured groin in a match before the knockout stages but it was obvious inside two minutes of going on after halftime it wasn't up to it.
It leaves the Kiwis vulnerable if anything happens to Johnson, Kieran Foran or hooker Issac Luke, with Elijah Taylor the fallback option at hooker and Williams the most likely alternative in the halves - he finished the game on Saturday at five-eighth. Tournament officials have indicated the Kiwis won't be able to replace Leuluai in the squad even if an alternative existed. Leuluai will likely remain with the team for the remainder of the tournament.
"He's a massive loss for us," Johnson said.
"There's no question what he means and what he brings to this side. I guess I need to step up and keep on heading in the right direction in building the combination with Kieran Foran.
"Tommy is still going to have a big part to play in how we go, I think. He's very experienced and we will use that."
There is brighter news on the injury front with Manu Vatuvei (knee) and Josh Hoffman (shoulder) both likely to be fit for Saturday morning's quarter-final against Scotland.
Centre Bryson Goodwin has a tight hamstring but should also be fine.