Rory McIlroy (left) and Graeme McDowell of Ireland wait to putt on the 7th hole before finishing equal first at 13-under during the 56th World Cup of Golf at Mission Hills in Haikou, Hainan province, on Friday. [Photo / Agencies]

HAIKOU, Hainan province - 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 pacesetters Australia.

World No 2 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 with the way I swung the club in general and Rory is playing lovely."

Current US Open champion McIlroy said: "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.

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's Michael Hendry and Gareth Paddison zipped up the leaderboard to tie fourth on 10 under with Spain and the US after shooting eight birdies during their impressive 68.

Host China was the second round's other big mover, to the acclaim of the home crowd, with Liang Wenchong and Zhang Xinjun carding six birdies and two eagles in their 68 to tie for 10th.

England's Ian Poulter and Justin Rose are tied for seventh with Mexico and the Netherlands.

The 28 national teams return to the four-ball format for the third round on Saturday on the Blackstone course at the Mission Hills golf resort.

Agence France-Presse