Put into bat, England lost three wickets in quick succession in the middle of the innings after a reasonably good start but young Root unleashed a stunning counter-attack to steer the total past the 250-run mark, which looked doubtful at one stage.
Root, who clobbered eight boundaries and a six during his 45-ball blitzkrieg, and Pietersen were largely responsible for England recovery, while captain Alastair Cook laid the foundation with a solid 76.
The visitors scored as many as 100 runs in the last ten overs as the Indians, who had the game under control for most part of it, suddenly appeared to lose the plot with Root and Pietersen going on the offensive.
Spinner Ravindra Jadeja was the pick of the Indian bowlers with 3/39 while Ishant Sharma 2/47 and R Ashwin 2/63 were the other wicket-takers on a Mohali track, which appeared to be good for batting.
England started their innings on a cautious note as the two Indian new ball bowlers, Bhuvneshwar Kumar and Shami Ahmed got the ball to move around in the initial overs.
Both Kumar and Shami, who proved to be a little expensive in the first spell, troubled the batsmen as openers Cook and Ian Bell played and missed on a few occasions. But they were lucky not to edge the ball.
With Shami giving away 18 runs in his first three overs, Indian captain Mahendra Singh Dhoni brought in Ishant Sharma from the pavilion end and the lanky seamer bowled a probing line and troubled the batsmen.
The opening pair put on 37 runs for the first wicket before Ishant provided the breakthrough by evicting Bell, who perished to a rash stroke.
