Ireland were put in and slumped to 111-6, before Niall O'Brien struck his fourth ODI half-century (52) and Trent Johnston (34) took them up to 193.
After a three-hour delay India were set 171 from 39 overs and they had a woeful start, Sachin Tendulkar out for four.
But Gautam Gambhir and Saurav Ganguly put on an unbroken 164 and India won with four overs remaining.
It was only Ireland's second home ODI and they will hope for a different result when they take on South Africa 'morrow.
India chose to field in seamer-friendly conditions and Sreesanth and Rudra Pratap Singh soon found some swing.
Sreesanth (3-50) quickly sent Kenny Carroll (seven) and Dominick Joyce (18) packing as the hosts struggled to get going in just their second home ODI.
Will Porterfield dropped anchor to try and help his side out of trouble, but he fell for 16 and then Gary Wilson (13), Kevin O'Brien (three) and Andrew White (eight) were all bamboozled by teenage leg-spinner Piyush Chawla.
Chawla playing his second ODI bowled extremely well for his 3 for 29 in 10 overs. He tormented Eire batsmen by mixing up leg-spinners with googlies and top spinners in a good measure.
It was left to the obdurate Niall O'Brien and his captain Johnston to move Ireland to respectability as they upped the tempo.
O'Brien hammered Singh for four but was out next ball in the 45th over, getting a leading edge to debutant middle-order batsman Rohit Sharma at cover.
Johnston continued to add to the total and hit Sreesanth for two massive sixes but he eventually holed out to Yuvraj Singh, before Roger Whelan was stumped off the last ball of the innings.
A prolonged downpour in Belfast put India's reply in danger, but after several inspections, play finally resumed after a three-hour delay with a revised target of 171 in 39 overs.
Whelan, who was making his ODI debut got rid of dangerous Tendulkar disturbing the laters timber with a peach of an inswinging delivery.
Gambhir joined Ganguly at the crease and, though the former skipper rode his luck at times, they never seriosuly looked like they would fail to reach their target.
Irish captain Johnston and Thinus Fourie both bowled economically, but the hosts rarely looked like taking enough wickets to provide India with a scare.
Ganguly eased to his 68th ODI half-century and he hit the winning runs off Fourie as India romped to victory.