The Showdown's intense rivalry can be traced back to Port Adelaide's pre-existing rivalries within the SANFL, particularly Norwood. The Norwood–Port Adelaide rivalry began in 1878 when the two clubs first played one another, however it was not until 1882 that the Norwood–Port Adelaide rivalry grew bitter. That year Port Adelaide's first win over Norwood, held at Adelaide Oval, was controversially overruled by the league, with a follow up game overshadowed by a misunderstanding at the gate which almost prevented Norwood players accessing the venue.