Australia skipper Aaron Finch missed out on a record third consecutive hundred by just 10 runs while Adam Zampa (4-43) and Pat Cummins (3-23) demolished Pakistan by 80 runs in the third ODI in Abu Dhabi.
Finch hit 90 off 136 balls to steer Australia to 266 for six after the visitors decided to bat first before the Australian bowlers folded Pakistan for 186 to seal the series.
Australia won the first two ODIs by identical margins of eight wickets.
After being rested in the first two ODIs, Cummins followed his 14 wickets in the series win in India earlier this month by dismissing Shan Masood (2) in his third over and then had Haris Sohail (1) and Mohammad Rizwan (0) in his fourth, leaving Pakistan reeling at 16-3.
Imam-ul-Haq (46) and Shoaib Malik (32) put on a 59-run fourth-wicket partnership before Glenn Maxwell trapped Imam in front.
Umar Akmal (36) and Imad Wasim (43) added another partnership of 53 runs for the sixth wicket but Zampa ripped through the lower order to seal the game with career-best figures.
The series win is Australia's sixth over Pakistan since 2002.
Finch, who scored 116 and 153* the first two ODI, could have been the first Australian to score three consecutive hundreds ODIs.
Kumar Sangakkara holds the record of most successive hundreds with four he scored during the 2015 ODI World Cup.
Finch's anchoring role was bolstered by Glen Maxwell later in the innings who smacked 71 off 55 balls to power Australia past 250.
Australia started shakily and lost opener Usman Khawaja (0) off just the fifth ball, bowled by Usman Shinwari. Junaid Khan dismissed Shaun Marsh for 14 to leave Australia struggling at 20-2 but Finch added 84 for the third wicket with Peter Handscomb (47) to help Australia rebuild.
Finch added another 36 with Marcus Stoinis (10) and 48 for the fifth wicket with Maxwell.
Maxwell and Alex Carey (25*) put on a quick 61 for the sixth wicket as Australia hit 90 in the last 10 overs.