PERTH (Australia): Australian captain Steven Smith won the toss and put Pakistan in to bat Thursday with the five one-day international series tied at one all.
Australia chose to rest star paceman Mitchell Starc.
He was replaced by rookie quick Billy Stanlake, who bowled just three overs in his international debut in Brisbane in the series opener last Friday before being forced from the field by illness.
Batsman Peter Handscomb was making his ODI debut and replaces the injured Chris Lynn, whose neck problem has ruled him out for the rest of the series.
Pakistan were buoyed by their drought-breaking six-wicket win in game two at the Melbourne Cricket Ground on Sunday.
It was their first win in Australia in any format for more than a decade and they made no changes to their team.
Australia: David Warner, Travis Head, Steve Smith (capt), Usman Khawaja, Peter Handscomb, Glenn Maxwell, Matthew Wade, James Faulkner, Pat Cummins, Billy Stanlake, Josh Hazlewood
Pakistan: Sharjeel Khan, Mohammad Hafeez (capt), Babar Azam, Asad Shafiq, Shoaib Malik, Umar Akmal, Mohammad Rizwan, Imad Wasim, Mohammad Amir, Hasan Ali, Junaid Khan
Umpires – Simon Fry (AUS) and Chettithody Shamshuddin (IND)
Third Umpire – Chris Gaffaney (NZL)