The West Indian made 73 runs off 51 balls while the Aussie scored 61 in 39 deliveries as United achieved the challenging 175 run target with ease in the 19th over.
No Gladiators bowler could put a stop to flow of runs throughout the United innings leaking too many bad deliveries much to the disappointment of Quetta fans.
Anwar, McCullum, Cheema and Zulfiqar Babar shared a wicket each for Gladiators.
Earlier, Ahmed Shehzad and Sri Lanka great Kumar Sangakkara also scored half-centuries to lift Quetta Gladiators to 174 for the loss of 7 wickets setting a 174 run target for United.
Gladiators lost two early wickets for 33 but then Shehzad and Sangakkara changed the scene adding 87 from 56 balls for the third wicket partnership. Shehzad made 64 runs off 39 deliveries with 9 fours and a six and the Islander scored a 32-ball 55, hitting 7 fours and two sixes.
Kevin Pietersen with run-a-ball 18, Anwar Ali 13 and Grant Elliott with 12 were the other notable contributors.
Andre Russell was the pick of the bowlers, grabbing three wickets for 31. Irfan took two while Badree and Mohammaf Sami shared a wicket each for United.
Islamabad United captain Misbah-ul-Haq had won the toss and invited Quetta Gladiators skipper Sarfraz Ahmed to bat first in the final of inaugural edition of Pakistan Super League (PSL) here at Dubai International Cricket Stadium earlier in the evening.
Speaking on the occasion, both skippers expressed their desire to win it for the people of Pakistan and revive the lost passion of cricket in the nation.
The two captains said they are fielding unchanged sides in the all-important game from their last matches.
National anthems of United Arab Emirates (UAE) and Pakistan were played at the start of the final with chief guest UAE’s Minister of Culture, Youth and Community Development Sheikh Nahyan bin Mubarak Al Nahyan shaking hands with players of the two teams.
Pakistan People’s Party (PPP) Chairman Bilawal Bhutto-Zardari and his sister Bakhtawar Bhutto-Zaradri were also present on the occasion.
Quetta skipper Sarfraz Ahmed believes that his players will go all the way.
“It is a very big opportunity for Quetta and the population of Quetta and for its cricket if we are to win. Whether we bat first or bowl doesn’t really matter. The key to us performing is our team bonding which has been very good throughout the tournament,” Sarfraz had said ahead of the final.
Both teams took a different route to the final: Gladiators did not break too much sweat during the league phase losing just two matches and became the first team to make the final. United took the more arduous route as they lost four matches in the group phase, but then bounced back with four consecutive wins.
In their previous two encounters, Gladiators successfully chased down the targets: they won the tournament opener with a whopping four overs to spare and a week later they won with 23 balls still in the bag.
Meanwhile, Pakistan Cricket Board (PCB) has asked fans without tickets to stay away from the Dubai International Stadium as the final is sold-out.
“For the convenience for all, as the final is sold out, please do not come to the venue on match day if you do not have a ticket as all tickets are sold out. The box office will be closed on match day,” the Board said in a statement.
Islamabad United: Sharjeel Khan, Dwayne Smith, Asif Ali, Brad Haddin, Khalid Latif, Misbah-ul-Haq (c), Andre Russell, Samuel Badree, Imran Khalid, Mohammad Irfan, Mohammad Sami
Quetta Gladiators: Bismillah Khan, Ahmed Shehzad, KP Pietersen, KC Sangakkara, Sarfraz Ahmed (c), Mohammad Nawaz, GD Elliott, NL McCullum, Anwar Ali, Zulfiqar Babar, Aizaz Cheema