The Bulldogs, first-place finishers in the regular season, had a two-try performance from New Zealand-born winger Sam Perrett before 70,300 fans at the former Olympic stadium in western Sydney
The Rabbitohs, co-owned by actor Russell Crowe, were attempting to advance to the grand final for the first time since 1971.
On Friday, the Storm scored a pair of early tries to beat the defending champion Manly Sea Eagles 40-12. Bulldogs coach Des Hasler led Manly to last year's title.
The grand final will be played next Sunday in Sydney.Suggest a correction