Virat Kohli scored an unbeaten 56 off 47 balls as tournament favourites India reached 142-5 in 19.2 overs after restricting Sri Lanka to 138-9 in 20 overs.
Medium pacer Hardik Pandya and Jasprit Bumrah claimed two wickets each for India giving away 26 and 27 runs respectively.
The Indian team overcame Bangladesh by 45 runs in their first match and then defeated Pakistan by five wickets in their second match of the tournament. Sri Lanka, on the other hand, edged out United Arab Emirates (UAE) by 14 runs and lost to the hosts by 23 runs.
India and Sri Lanka have played nine matches against each other in which the Men-in-Blue have won five games while the Lankans have won four.
India XI: Rohit Sharma, Shikhar Dhawan, Virat Kohli, Suresh Raina, Yuvraj Singh, M.S. Dhoni (captain), Hardik Pandya, Ravindra Jadeja, Ravi Ashwin, Jasprit Bumrah and Ashish Nehra.
Sri Lanka XI: Dinesh Chandimal, Tillakaratne Dilshan, Shehan Jayasuriya, Angelo Mathews (captain), Milinda Siriwardana, Dasun Shanaka, Chamara Kapugedera, Thisara Perera, Nuwan Kulasekara, Rangana Herath and Dushmantha Chameera.