Sandon Smith's tap-and-go, taken after the referee marked the spot, helped decide the Roosters' Finals win over Penrith.
Penrith were caught off guard.
Sydney and Newcastle now contest the NRL Premiership after 27 rounds and three Finals weeks eliminated 15 other teams.
The Grand Final also tests last off-season's Roosters decision to pursue Dally Cherry-Evans while allowing Smith to leave.
It will either end the "50 point stat"-no NRL-era team that conceded 50 points has won-or crown the first champion from outside the top four.
The first NRL send-off for a hip-drop tackle, after Nathan Cleary was injured, split opinion.
The writer says injury should count, as in high-tackle decisions, and argues hip drops must be removed.
Ashley Klein's Bunker appointment after a disputed Finals performance prompted criticism; the writer says he should not referee the Grand Final.