I would rather play India then Australia.
You don't beat Australia twice in the same competition.Not when they just beat the home team.
Coming to India,they have WC history on their side,but this time i'm confident of our chances against them.The pressure will be squarely on India - home crowd,home conditions,expectant country,WC semifinal,against the arch rival,favorable WC head to head etc.
Pakistan will have a fair bit of pressure on them too,but since they came into the tournament as underdogs,and they never had the same weight of expectation on them as the Indian team,they will be under less pressure.
It's all about how handles the pressure well.India have to deal with an infinite amount of more pressure than Pakistan due to their pre-tournament favorite status and home crowd,which is where i think they will collapse.