Rory McIlroy and Graeme McDowell combined for a four under par 68 in the second round foursomes at the Omega Mission Hills World Cup in China to maintain their three shot advantage.

The two Ulstermen were not in the electric form that saw them card a remarkable 58 in the opening fourballs but an outward 32 ensured they preserved their advantage by reaching 18 under.

After starting with three consecutive pars to allow Argentina to trim their advantage to two, McIlroy played a superb approach over the pin at the par four fourth to set up McDowell to roll home from eight feet to restore the overnight lead.

McDowell then nailed his approach to the par five seventh to leave McIlroy with a straight-forward eagle putt.

Another birdie followed at the ninth when McDowell holed from ten feet after his partner’s deft chip from the edge of the green before a bogey on the 11th and a double bogey at the par five 15th when McDowell found the water.

But that blemish to the scorecard was quickly forgotten as the pre-tournament favourites birdied the next two holes.

World Number Ten McIlroy, who narrowly missed out on The Race to Dubai title to Lee Westwood just a week ago, said: “We started out the day with a three shot lead and we still have a three shot lead, so it was a good day.

“Foursomes is a little trickier than the fourball, if you hit it in trouble, you're relying your partner to get you out, where you're taking responsibility for your own actions a bit more whenever you're playing in the fourball.

“I think we probably would have taken 68 on the first tee. We had a go today to get a bit lower than that but we played very solidly. Apart from the couple of mistakes on the back nine, we could have got a really good score in there, but I think in the end we showed really good character to come back with two birdies on 16 and 17 after the double on 15.”

Defending champions Sweden emerged as Ireland’s nearest challengers - Robert Karlsson and Henrik Stenson signing for a seven under par 65.

The Molinari brothers Francesco and Edoardo, representing Italy, are a shot further back on 14 under following a 66.

The experienced Swedish duo have not dropped a shot over two rounds and Stenson is looking to maintain the pressure on leaders Ireland over the weekend after applying some to teammate Karlsson over the closing holes of the Olazábal course.

“I definitely put him [Karlsson] under pressure a few times on the back nine,” said the Players Championship winner. “I left him a couple nice three, four and five footers for par. Robert did great and I think the way the course played, we had a different thought when we started the tournament last year on Thursday that I was going to hit on the odd holes, but then we spoke and came up with me hitting on the even ones instead.

“I think the way the golf course plays, it fits our game perfect. Robert drives the ball really nice and I've been hitting some good iron shots, and today we made some putts, as well. We just need to keep on playing as well as we have the first two days for the next two days, and we'll have a chance.”

Still not out of contention are Japan on 11 under, with Wales and surprise package Venezuela on ten under par.

England, India, New Zealand and South Africa will all need something special over the closing rounds from nine under par to catch the Irish.