In a match where there were numerous rain-interruptions, Pakistan were bundle out for 165 in 39.4 overs due to a disciplined effort by the Indian bowling unit led by Bhuvneshwar Kumar, who returned with figures of two for 19.
India's final revised target courtesy D/L method was 102 in 22 overs which the 'Men In Blue' achieved with 17 balls to spare as Shikhar Dhawan again blazed his way to a 41-ball-48.
India thus finished group league engagements with an all-win record.
Winning the 'prestige battle' against Pakistan will certainly be a big morale-booster for Mahendra Singh Dhoni's men as they await their semi-final opponents whom they will take on in the second semi-final in Cardiff on June 20.
The win was also India's first in the Champions Trophy having lost against the same opponents in the 2004 and 2009 editions of the tournament.
With game frequently delayed by intermittent rain, India never lost sight of the target as the openers Dhawan and Rohit Sharma (18) again gave a solid start adding 58 runs for the opening stand. While Rohit was a bit subdued, there was no stopping Dhawan who repeatedly peppered the off-side field.
In all he hit five boundaries and just when a half-century was there for the taking, the Delhi lad slashed hard at one from Wahab Riaz to be caught at the deep third-man boundary. Virat Kohli (22 no) and Dinesh Karthik (11 no) ensured that there were no hiccups in the chase.
Earlier, India's bowling quartet of Bhuvneshwar, Ravichandran Ashwin, Ravindra Jadeja and Ishant Sharma shared the bulk of the spoils as they never really let Pakistan batsmen off the hook.