India, who had already qualified for the semi-finals, scored 159-7 after being sent in to bat and then bowled out Australia for 86 in 16.2 overs to top group two.
It was Australia's third loss in a row, leaving them at the bottom of the table along with Bangladesh.
Pakistan, who beat Bangladesh by 50 runs earlier on Sunday, will clash with the West Indies on Tuesday to decide the second semi-finalist from the group.