From 16/2, Jonathan Trott (44) and Pietersen (73) struck a 86-run partnership to take England out from a spot of bother. Trott and Pietersen hit seven and 10 boundaries, respectively, in their innings before the former was bowled by another debutant Ravindra Jadeja in the 50th over.
Ian Bell (1) also fell soon after as he was lured into a drive by leg-spinner Piyush Chawla and was caught at short cover by Virat Kohli.
Pietersen was the last wicket of the day after which Root and Prior held the innings together for the next 30 overs and scored another 60 runs.
In Image: Kevin Pietersen stretches during drinks break