The 27-year-old, after centuries in his two previous innings, was unfazed by the stop-start nature of his innings as he extended his overall tally to 264 with 48 off 41 balls.
That was enough to guide India to an eight-wicket Duckworth-Lewis method victory and a 50th one-day international success over their sub-continental neighbours.
Wet weather disrupted throughout and severely dampened down the atmosphere produced by a sell-out 22,832 crowd who expected much despite this being a dead rubber with one side already in the semi-finals and the other eliminated.
However, Pakistan failed for the third match in a row to score more than 170, finishing with 165.
India were initially set a revised target of 168 off 40 overs only for one rain shower to cut it to 157 in 36 and a second to bring it down to 102 in 22 overs.
But Pakistan looked demoralised from the moment they took to the field and India compounded that as they scored runs freely.
They were well ahead of the Duckworth-Lewis requirement at 63 for one in the 12th over when the rain returned for a second spell, which left them needing 39 in 10.3 overs on resumption.
Rohit Sharma fell with the score on 58 in the 11th over then Dhawan was caught off Wahab Riaz with 24 still required but India cruised home with 17 balls to spare thanks to an unbeaten 22 from Virat Kohli.