The Red Rose have already secured their first ever series win Down Under and hold an unassailable 2-0 lead in the three-match series, with Saturday's clash in Sydney the final instalment.
“We treated this week like a dress rehearsal for the World Cup because that’s what we’re always building towards,” said Jones.
“To win a World Cup you have to win three big games in a row. We’ve won two so this third game is the most important game we’ll play all year. It will be a good indication of where we are as a team.”
Jones has opted to make just one change to his starting XV from last week’s 23-7 victory in Melbourne after wing Jack Nowell passed concussion protocols. Northampton flanker Teimana Harrison is set to start in place of the injured James Haskell.
“You have to work extremely hard to earn an England cap so there was no temptation to make changes for the sake of change,” added Jones. “To play for England you have to be in the best 23 and that’s what this selection represents.”