Mission Hills - Ireland's powerful pairing of Rory McIlroy and Graeme McDowell stayed out in front at the World Cup on Friday, but defending champions Sweden powered back into contention.
Ireland, who took a three-shot lead into the foursomes after a blistering first round fourballs, made five birdies and an eagle to lead by three strokes after 36 holes on the bunker-strewn Olazabal Course at Mission Hills.
Sweden, featuring world number seven Henrik Stenson and 2008 European Order of Merit winner Robert Karlsson, moved to 15-under following the only blemish-free round of the day, which included seven birdies.
The Italian team, made up of the Molinari brothers, Francesco and Edoardo, were on 14-under with Japan a further three shots back and Wales and Venezuela on 10-under.
McDowell and McIlroy, who finished second on the European money list, were unable to repeat their first-round heroics, but were off to a good start after two birdies and an eagle on the front nine, giving them a five-shot lead at the turn.
They dropped their first shot of the tournament on the par-five 11th and a double-bogey seven at the par-five 15th after McDowell found the water threatened to cost Ireland dear.
But they struck birdies on the 16th and 17th to leave themselves with a three-shot cushion going into the second round of fourballs on Saturday.
Sweden followed up their opening day 64 with a seven-under round featuring seven birdies, including a 20-foot Stenson putt at the par-three 17th.
But the Spanish challenge, led by Sergio Garcia, ranked eighth, continued to falter and they ended the day on four under, effectively out of contention.
England, with Ian Poulter and Ross Fisher, were nine under after 36 holes.
Scores on Friday after the foursomes second round of the $5.5 million Omega World Cup:
126 - Ireland (Graeme McDowell/Rory McIlroy) 58-68
129 - Sweden (Robert Karlsson/Henrik Stenson) 64-65
130 - Italy (Edoardo Molinari/Francesco Molinari) 64-66
133 - Japan (Hiroyuki Fujita/Ryuji Imada) 62-71
134 - Venezuela (Alfredo Adrian/Jhonattan Vegas) 67-67, Wales (Stephen Dodd/Jamie Donaldson) 66-68
135 - India (Jyoti Randhawa/Jeev Milkha Singh) 67-68, New Zealand (Danny Lee/David Smail) 67-68, England (Ian Poulter/Ross Fisher) 66-69, South Africa (Rory Sabbatini/Richard Sterne) 65-70
136 - Chile (Hugo Leon/Martin Ureta) 69-67, Singapore (Lam Chih Bing/Mardan Mamat) 66-70, China (Zhang Lianwei/Liang Wenchong) 65-71, Denmark (Soren Kjeldsen/Soren Hansen) 66-70, Argentina (Tano Goya/Rafael Echenique) 61-75
137 -Thailand (Prayad Marksaeng/Thongchai Jaidee) 67-70, Germany (Alex Cejka/Martin Kaymer) 66-71
138 - Australia (Stuart Appleby/Robert Allenby) 68-70, Canada (Graham Delaet/Stuart Anderson) 64-74
139 - USA (Nick Watney/John Merrick) 67-72, South Korea (Charlie Wi/Yang Young-Eun) 64-75
140 - Spain (Gonzalo Fernandez Castano/Sergio Garcia) 69-71, Philippines (Marciano Pucay/Angelo Que) 68-72, France (Christian Cevaer/Thomas Levet 67-73
141 - Taiwan (Lin Wen-tang/Lu Wei-chih) 67-74
142 - Scotland (David Drysdale/Alastair Forsyth) 69-73
143 - Brazil (Rafael Barcellos/Ronaldo Francisco) 68-75
144 - Pakistan (Muhammad Munir, Muhammad Shabbir) 69-75