While Rahane exquisitely compiled 111, Dhawan clobbered the bowlers en route to 113 to help the team to a mammoth total for India.
Seasoned campaigner Mahela Jaywardene put up some resistance with a fiery 43 off 36 balls for the Lankans but other batsmen failed to put up fight.
Ishant Sharma was the pick of Indian bowlers picking 4 wickets for 34 runs. Yadav and Patel took 2 wickets each.
Man of the Match was Ajinkya Rahane for his match-winning 108-ball 111.
2nd ODI will be held on November 06 at Sardar Patel Stadium, Ahmadabad.