Opting to bat, Sri Lanka were restricted to a modest total of 113 for 9 in 20 overs.
Radha Yadav starred with the ball for India, picking 4 wickets for 23 runs while Rajeshwari Gayakwad bagged two. The duo was well supported by Poonam Yadav, Shikha Pandey and Deepti Sharma, who all got a wicket each.
Chamari Athalaththu top-scored for Sri Lanka with 23-ball 34 including five fours and one six while Kavisha Dilhari scored 25 not out.
In reply, India Women chased down the target with 32 balls to spare and 7 wickets in hand.
Opener Shafali Verma played yet another brilliant innings before being run out for 34-ball 47.
Smriti Mandhana contributed with 12-ball 17. Harmanpreet Kaur promoted herself up the order and scored 15, her first double-digit score in the tournament.
Deepti Sharma and Jemimah Rodrigues stayed unbeaten for 15 each as India stretched their winning streak.
Udeshika Prabodhani, Shashikala Siriwardene picked one wicket each for Sri Lanka.
Spinner Radha Yadav was given the Player of the match award for her career best bowling figures of 4 for 23.
Sri Lanka: 113/9 in 20 overs (Chamari Atapattu 33; Radha Yadav 4/23)
India: 116/3 in 14.4 overs (Shafali Verma 47) (UNI)