At the Finnish capital Helsinki's Hartwall Areena, Gaga fired a f-word rant at Madonna, who's openly accused her rival of copying her song 'Express Yourself', reported Mirror online.
Gaga imitated the 53-year-old Material Girl's earlier onstage antics by flashing her derriere in fishnet stockings and a thong and yelling: "I don't give a (damn) what people say. We don't give a (damn). We know the truth."
Madonna has been singing Gaga's song 'Born This Way' during her MDNA tour in an effort to make some kind of ironic joke.
Gaga, 26, returned the favour by bringing on stage her own Black Jesus character, like that of Madonna's video for 1989 hit 'Like A Prayer', and performed a cover of the track.