HAINAN - Celtic champions Rory McIlroy and Graeme McDowell engineered a two-shot lead to put daylight between Ireland's World Cup claim and a chasing trio of golfing powerhouse nations on Saturday.

World No 2 McIlroy and 2010 US Open winner McDowell fired eight birdies in the four-ball third round to card a sterling 8-under 64.

They remain top of the leader board on 21 under overall, nudging ahead of the sizzling Teutonic pairing of world No 4 Martin Kaymer and Alex Cejka, who holed 11 birdies in their ground-making 61.

"We made lots of birdies and always on different holes, and I played very well today," said Kaymer.

"But obviously you can only play well and be aggressive if you have a partner who is playing very consistent and is always there for you," he said.

Germany is tied second with big hitters South Africa and the US on 19 under.

South Africans Charl Schwartzel and Louis Oosthuizen wooed the modest crowd with their powerful tees, as the duo carded an impressive 11-under 61 and sunk 11 birdies.

The resurgent US team of Gary Woodland and Matt Kuchar ensured their hands were still within touching distance of the trophy going into tomorrow's fourth round with a 9-under 63.

Australia slipped to fifth as Brendon Jones and Richard Green struggled in the wet and humid conditions at the Mission Hills complex, but it still stayed close to the leaders on 18 under.

Defending champions Edoardo and Francesco Molinari of Italy put themselves back into contention with a 8-under 64 and are tied 7th with Mexico on 16-under.

England's Ian Poulter and Justin Rose also made heavy work in the fickle conditions, seeing their hopes of lifting the trophy disappear in the steamy atmosphere.

They carded two bogeys in their four-under 68 and are joint 15th with Zimbabwe on 13 under.

Home hopes for a fairytale victory were dashed as China's Zhang Xinjun and Liang Wenchong slipped to joint 17th on 12 under.

Sunday's final round of the $7.5 tournament will see a return to the tricky foursomes alternate shot format.

Agence France-Presse