Both the batsmen played aggressively sharing 68 runs on fourth wicket. Pietersen smashed three sixes while Nawaz struck the ball over the boundary for two times.
Earlier Skipper Quetta Gladiators, Sarfraz Ahmed won the toss and elected to bowl first.
Hassan Khan, Shane Watson, Rahat Ali, Anwar Ali, John Hastings shared one wicket apiece to down the strong batting line of Islamabad.
Islambad openers Luke Ronchi and Walton were completely failed to provide a good start to their team as Walton got Leg before wicket off Anwar Ali after scoring eight runs. Quetta got their first breakthrough on 13 runs.
Luke Ronchi added quick 43 runs before he was bowled off an arm delivery from young Hassan Khan. His innings was laced with seven boundaries and a loan six.
Islamabad middle order showcased poor show as Asif Ali (6), Duminy (14) were departed one after the other.
Misbah-ul-Haq who recovered from injury and played his first match of this season scored a snail-pace innings of 22 runs.
Young duo of Faheem Ashraf and Hussain Talat scored handy partnership of 29 runs in death overs.
Fahim got run-out in 20th after hitting the last ball of the 19th over for a six. He scored 21.
Quetta in reply reached the target with six wickets in hand. Asad Shafiq contributed 22 runs to the total.
Steven Finn got three while Muhammad Sami claimed one wicket.
Kevin Pietersen awarded Man-of-the match.