South Sydney's beaten reigning premiers Melbourne 20-10 in the opening game of the National Rugby League finals.
The victory puts South Sydney one win away from a grand final berth and came after the Rabbitohs led 14-0 at half-time.
But a late and controversial no-try call from the video referee ruined what would have been Storm fullback Billy Slater's second try, and Kiwis hooker Issac Luke then sealed the win with the Rabbitohs' third try in the 67th minute.
A late consolation try to Will Chambers wasn't enough and Melbourne will now host a sudden death semi-final next Saturday night against the wnner of tomorrow's second elimination final, between the Canterbury Bulldogs and the Newcastle Knights.
The loser of tonight's first qualifying final between minor premiers the Sydney Roosters and the Manly Sea Eagles next faces the winner of tonight's first elimination final, between the Cronulla Sharks and the North Queensland Cowboys.
In the night's under-20 elimination final, the Junior Warriors squeaked past the Junior Rabbitohs 20-18.