Rory McIlroy and Graeme McDowell posted six birdies in a 68 to put Ireland into a tie for the lead with Australia after two days of the World Cup in China.
Australian pair Brendan Jones and Richard Green were unable to match their opening day 11-under-par 61 but a round of 70 saw them also at 13 under.
Martin Laird and Stephen Gallacher of Scotland are one shot back after a 69.
England's Ian Poulter and Justin Rose played the back nine in five under and are four off the lead in joint seventh.
McIlroy and McDowell were satisfied with their performance in the alternate shot format on the southern Chinese island of Hainan, with humid, wet and windy conditions evident on day two.
"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."
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.
"There is still a lot of golf to be played this week so it will be nice to get out there tomorrow again and enjoy the fourballs and be aggressive and make a few more birdies."
The Australian pair of Jones and Green picked up two birdies and an eagle in the opening six holes before dropping two shots in the closing four holes.
"It's a very stressful game," Jones explained. "It's very difficult, because it's very hard to get any sort of rhythm in your golf swing in your game, because you might go four or five holes without hitting a driver. You might go a few holes without having a putt."
Green said: "We spoke about our strategy last night, and in foursomes especially we decided that anything under par in this form is going to do all right. So a 70 achieved that goal I guess."
Scottish duo Laird and Gallacher could have ended the day in a share of the lead but for a bogey at the last.
To the delight of the home crowd, Liang Wenchong and Zhang Xinjun carded six birdies in their 68 to lift China into a share of 10th, five shots off the pace.
The 28 national teams return to the fourballs format for the third round on Saturday on the Blackstone course at the Mission Hills golf resort before the biennial event reverts to foursomes for Sunday's final round.