HAINAN (AFP) - Irish dynamos Rory McIlroy and Graeme McDowell carded a second-round four-under 68 at the $7.5-million World Cup to ease into tied first place with pace-setters Australia on Friday. World number two McIlroy and 2010 US Open champion McDowell shot six birdies and two bogeys during the challenging foursomes alternate shot format on the muggy southern Chinese island of Hainan. "We struggled to find our rhythm a little bit on the front nine. Rory putted really well today, which kept things together," said McDowell. "I've struggled a little bit on the greens the last couple of days. But I was happy the way I swung the club in general and Rory is playing lovely." Current US Open champion McIlroy added: "I think both of us are very pleased about the score that we ended up shooting today. "Anything in the 60s in the foursomes format is a very reasonable score out there." Determined Australians Brendan Jones and Richard Green crafted an eagle and three birdies in their 70, but were undone with two bogeys in the humid, wet and windy conditions. "We spoke about our strategy last night, and we decided that anything under par in this form is going to do all right. So a 70 today achieved that goal I guess," said Green. He added: "It's a bit of a shame to have finished with a bogey. But it's a very difficult finish to this golf course and a very demanding 18th hole. Hopefully we can work that out for the weekend and not do that on Sunday." They and the Irish pairing top the leaderboard on 13-under-par 131 after two days. Scottish stalwarts Martin Laird and Stephen Gallacher fired four birdies in their 69 to secure third place on 12 under overall. New Zealand pairing Michael Hendry and Gareth Paddison zipped up the leader board to tie fourth on 10 under with Spain and the USA after shooting eight birdies during their impressive 68. Hosts China were the second round's other big movers, to the acclaim of the home crowd, with Liang Wenchong and Zhang Xinjun carding six birdies and two eagles in their 68 to tie 10th. England's Ian Poulter and Justin Rose are in tied seventh with Mexico and the Netherlands. The 28 national teams return to the fourballs format for the third round Saturday on the Blackstone course at the Mission Hills golf resort.