With the top 12 performing live for the first time, Mel B, Guy Sebastian, Natalie Bassingthwaighte and Ronan Keating took to the stage to open the show.
Sebastian - who is mentoring the Under 25's - began with his number one track 'Who's That Girl'. Former Neighbours star Bassingthwaighte joined in with her 2009 hit 'Someday Soon', while Ronan Keating sang 'Lovin' Each Day'.
Mel B was the last judge to arrive on stage, singing the Spice Girls' hit 'Who Do You Think You Are', with the other three judges joining in for the finale of their group performance.
The results show, which featured a performance from Bryan Adams, also saw the final 12 acts perform Pink's hit 'Raise Your Glass' together.
The X Factor Australia continues next Monday and Tuesday on the Seven Network.
> Aussie 'X Factor' top twelve revealed
> Natalie Bassingthwaighte: 'Mel B needs a slap'