Shikhar Dhawan scored his second hundred of the tournament as India won their fifth straight World Cup game, beating Ireland by eight wickets in Hamilton.
Dhawan (100) hit 11 fours and five sixes in a blistering 85-ball knock - his eighth ODI ton - as he and his opening partner Rohit Sharma (64) notched India’s highest ever opening partnership in a World Cup.
The pair put on 172 together as India chased down Ireland’s 260-run target inside 37 overs, guaranteeing them top spot in group.
Mohammed Shami continued his good form with three for 41 from his nine overs as Ireland collapsed from a promising position of 206-3 after fifties from Niall O’Brien (75) and captain Will Porterfield (67).
After Ireland won the toss and chose to bat first, Porterfield and Paul Stirling (42 off 41 balls) put on their own record partnership of 89 - the largest by the team against a top-eight nation.
But in response MS Dhoni turned to his spinners for 22 straight overs which stifled the Irish scoring.
Stirling fell, lofting a simple catch to long-off off Ravichandran Ashwin (2-38), Ed Joyce - centurion in their last game against Zimbabwe - was bowled by Suresh Raina for just two.
That led to a rebuilding effort from the Irish with fifty partnerships between Porterfield and O’Brien, and then Andy Balbirnie (24) after Porterfield was picked up by Mohit Sharma.
O'Brien went through to his 14th ODI fifty with a six but Balbirninie’s dismissal - sweeping Ashwin to square-leg - in the 39th over signalled a collapse as the final six wickets fell for just 51 runs, Shami picking up three of them, including the key strikes of O’Brien, and his brother Kevin for one.
No other batsmen passed double figures except for last wicket pair of John Mooney (12no) and Alex Cusack (11) who added 21 together before Shami picked up the latter as Ireland finished on 259 all out with an over to spare.
India’s chase was emphatic - rocketing to 73 without loss from the first 10 overs. Dhawan and Sharma both eased to fifty and hit a combined eight sixes during their electric partnership.
Dhawan was dropped twice, first on five when Mooney failed to hold on to a fierce caught-and-bowled chance and then five runs later at backward point by Porterfield, Mooney again the unlucky bowler.
When they eventually struck, Sharma chopping on to his stumps off Stuart Thompson (2-45) soon after the pair broke the record for highest opening partnership by India in a World Cup, 174 runs were on the board.
Dhawan also fell to Thompson soon after notching his hundred, Porterfield taking a good catch over his shoulder at cover to atone for his earlier error.
The mini-wobble was soon corrected though with Virat Kohli (44no) and Ajinkya Rahane (33no) easing India through to a comfortable win.
Ireland now face a must-win clash against Pakistan in Adelaide on Sunday in order to secure a quarter-final spot, while India play Zimbabwe in Auckland the day before.
Watch highlights of India’s win over Ireland throughout the day on Sky Sports World Cup (channel 403) or with Hindi commentary on Zee Cinema (channel 790).