O'Sullivan was talking for both codes when he said.
"The Irish supporters are the best in the World if you give them something to cheer about.
Specifically relating to Ireland's World Cup challenge, which has already been deemed a success on account of guaranteed qualification for the last eight, he said.
the Irish Diaspora has bought into the World Cup and our boys appreciate that. The support at our three matches so far has been unbelievable. Saturday next will be the same - but that can also bring its own pressures.
Only slight cause for concern on the injury front concerns Victor Costello (thigh) and Kevin Maggs (ankle), both of whom sat out today's training. Maggs, on the orders of physio Ailbe McCormack had his right foot placed in a case of ice as he sat under a flimsy canopy offering bare relief from a chilly wind and heavy rain that dogged the session. A cup of tea was a life saver for him! But once more a bewildering reminder that bad weather has followed the Irish around Australia since their arrival almost a month ago.
Meanwhile, O'Sullivan's response to the boast from his opposite number Eddie Jones that he had two fully fit players in every position ready to go, was.
They can only put 15 players on the pitch - same as us. They have more depth and they are fully loaded. But if we can play with a full deck we can play with anyone. Plus we have the support, its going to be like a home Six Nations match for us.