Just one Knight played over the weekend, as Jacob Saifiti came from the bench for Fiji and Chris Heighington remained a reserve for England.
On Friday night Saifiti's Fiji went down 54-6 to Australia, with the twin suffering an early injury scare.
He was able to return later in the match though, clocking up 52 metres from four runs in 29 minutes.
AUSTRALIA 54 defeated FIJI 6
In the other semi final Chris Heighington watched from the sidelines as England scraped past Tonga 20-18 on Saturday night in Auckland.
Heighington's England now advance to the World cup final in what will be a re-match of the first game of the tournament against Australia.
ENGLAND 20 defeated TONGA 18