HAMILTON: Shikhar Dhawan hit an aggressive century as defending champions India recorded their fifth victory in a row at the World Cup with a thumping eight-wicket win over Ireland in Hamilton on Tuesday.

Chasing a modest 260-run target, Dhawan notched his second century of the tournament with an 85-ball 100 as India lost only two wickets in only 36.5 overs on a batting-friendly Seddon Park pitch.

This latest victory meant India, yet to lose at this World Cup and already into the quarter-finals, were guaranteed to finish on top of Pool B ahead of their last group game against Zimbabwe in Auckland on Saturday.

Ireland, meanwhile, will likely need a win against Pakistan in their last Pool match in Adelaide on Sunday to reach the last eight.

“We have put in a lot of yards in the last few weeks. It is all about being fresh for Pakistan. If you can't get up for these games you won't be up for any,” said Ireland captain William Porterfield.

Pakistan, Ireland and South Africa, who all have six points in five matches, will vie with the West Indies (four points) for the three remaining quarter-final spots on offer from Pool B.

“Our bowlers are really doing the job for us, they've stepped up — not just the three fast bowlers, the spinners are complimenting them and when we've used part-timers they've done well,” said India skipper Mahendra Singh Dhoni.

Ireland's Niall O'Brien scored a run-a-ball 75 while Porterfield made a solid 93-ball 67 in Ireland's 259 all out in 49 overs.

India proved their strength in batting yet again as Dhawan and Rohit Sharma (64) put on their team's best World Cup opening stand of 174 against a struggling Irish attack.

Dhawan, who stroked 137 in the win over South Africa, completed his eighth one-day international hundred with a single off Kevin O'Brien to square leg. He reached three figures off just 84 balls.

But one ball later Dhawan fell to a loose shot off Stuart Thompson. In all, Dhawan hit 11 fours and five sixes.

Rohit was dismissed when he played on to Thompson after hitting three sixes and as many boundaries off 66 deliveries.

India's previous best opening stand in a World Cup was the 163 shared by batting great Sachin Tendulkar and Ajay Jadeja against Kenya at Cuttack in 1996.

Virat Kohli (44 not out) and Ajinkya Rahane (33 not out) wrapped up the chase with a 70-run unbeaten stand for the third wicket to give Dhoni his ninth straight win in the World Cup, a run that started with the team's march to the 2011 title on home soil.

Australia's Ricky Ponting holds the record for the most consecutive World Cup wins as captain with 24, while Dhoni and Clive Lloyd, who led West Indies to victory in the first two editions in 1975 and 1979, have nine apiece.

Earlier, Ireland failed to capitalise on a good solid start.

Batting first after winning the toss, Ireland were 89 without loss in 15 overs, with Paul Stirling (42) giving good support to skipper Porterfield.

Stirling hit four boundaries and two sixes during his 41-ball knock before holing out to off-spinner Ravichandran Ashwin, who finished with two for 38.

Part-timer Suresh Raina bowled Ed Joyce for two before Porterfield and Niall O'Brien added a valuable 53 for the third wicket.

But once Porterfield fell, caught off paceman Mohit Sharma, Ireland slumped from 206 for three to 259 all out in 49 overs. Mohammad Shami grabbed the key wicket of dangerman Kevin for only one run to finish with figures of three for 41.

Niall O'Brien completed his 14th ODI half-century with a six off Ashwin but fell to a soft dismissal off Shami when Ireland needed him to stay till the end.

Andy Balbirnie, one of Ireland's most successful batsmen in the tournament, made 24 before he swept Ashwin straight to Shami at square-leg.