The bench was similarly impactful in South Africa’s warm-up win over New Zealand, with Jacques Nienaber introducing seven forwards at once to dominate the second-half set-piece battle and seal victory.
New Zealand, however, fared much better in the Rugby Championship meeting between the two nations earlier in the year, a game in which Williams made his debut.
And the 144kg prop believes that experience will stand him (if involved) and his colleagues in good stead at the Stade de France on Saturday.
“It’s clear they’ve got a good bench. They do damage when they come on,” said the 23-year-old, who came on at loosehead in the second half of the All Blacks’ semi-final win over Argentina.
“It is about whatever the team needs us to do off the bench – [adding] energy with our voice, energy with our ball carrying, our set piece.
“There is a lot of talk about them but we are just going to focus on ourselves and make sure we are primed. When the bench comes on, we need to make sure we make an impact.”
The gigantic Williams has risen quickly over the last couple of years after impressing for the Crusaders in Super Rugby Pacific.
Born in Whangarei, New Zealand’s northernmost city, he spent the majority of his childhood in Perth, Australia.
Having come through as a loose forward, Williams was a late convert to prop, but is skilful enough to cover both sides of the front row.
And he is braced for a significant challenge this weekend on the sport’s biggest stage.
“They are massive,” Williams quipped of the South African forwards. “And they are clinical – if you give them a chance, they’ll take it.
“It’s been a great learning, playing against them – I had a good win against them and we got a hiding against them as well.
“For us, it’s all about being clean. You’ve got to match the physicality they are going to bring. Everyone knows what they are going to bring, it is up to us to stop it.”