Kevin Pietersen scored 130 and Saeed Ajmal took three wickets. England overhauled the victory target in 49.2 overs for the loss of 6 wickets.
Earlier Pakistan set England a target of 238 to clinch the fourth one day international cricket match.
Asad Shafiq top-scored for Pakistan with 65 as the Green Shirts were bowled out for 237 after winning the toss. Jade Dernbach with 4-45 was England's most impressive bowler.