The Australian skipper smashed 143-ball 153 not out for his 13th ODI hundred -- also his highest score in ODIs -- to anchor Australia's comfortable chase of a 285-run target in 47.5 overs which gave them a 2-0 lead in the five-match series.
Finch, who scored 116 in Australia's eight wicket win in the first game at the same venue on Friday, put on a solid 209-run opening wicket stand with Usman Khawaja who made 109-ball 88.
Finch struck six sixes and 11 boundaries in a dominating innings, improving on his previous highest one-day score of 148 against Scotland at Edinburgh in 2013.
The victory becomes more memorable as it was 100th one-day international match between the two countries.
Pakistan had replaced fast bowler Mohammad Amir with Mohammad Hasnain for rookie 18-year-old's first one-day and that left them more deeply inexperienced, having already rested six main players from the series.
Finch and Khawaja thrived against the novice attack, with Finch striking two sixs in the final overs while Khawaja's knock had eight boundaries.
Finch completed his hundred with a couple off Hasnain on his 97th ball, making successive hundreds for a second time in his career. He scored consecutive hundreds against England in Australia last year.
Khawaja fell to leg-spinner Yasir Shah with 76 needed while Glenn Maxwell cracked two sixes in his 19 before he was run out.
Pakistan owd their total of 280-7 -- after winning the toss -- to Mohammad Rizwan's maiden century.
Rizwan, only playing because regular keeper and skipper Sarfraz Ahmed has been rested for the series -- added 52 for the third wicket with Haris Sohail (34) and an invaluable 127 for the fifth wicket with stand-in captain Shoaib Malik.
Pakistan lost opener Imam-ul-Haq without scoring off the fifth ball of the innings from fast bowler Jhye Richardson.
Shan Masood (19) and Sohail -- who scored his maiden hundred in the first game on Friday -- took the total to 35 when Richardson struck again, getting Masood caught at short mid-wicket.
But Richardson took 2-16 in his five overs and fell awkwardly in the outfield and left the field in the 11th over. Initial reports suggests he dislocated his shoulder and is doubtful for the remaining three matches.
Rizwan, though, lifted Pakistan after Umar Akaml fell for 16, caught off spinner Nathan Lyon.
Rizwan improved on his previous best of 75 not out, against Zimbabwe at Harare four years ago and completed his hundred with a single off 114 balls. He fell to Nathan Coulter-Nile to a boundary catch.
Coulter-Nile finished with 2-52.
Malik also smashed three boundaries and a six before falling in the 45th over.
The remaining matches are in Abu Dhabi (March 27) and Dubai (March 29 and 31).
First Published: March 25, 2019, 1:08 AM IST