Melbourne - Belgium and South Korea held their nerve in wild weather to take a two-shot lead in the second round of the World Cup of Golf on Friday as the wintery conditions wreaked havoc.
They have the edge over a chasing group of four - Italy, India, Malaysia and England.
It was tough going with icy winds and relentless rain causing big problems for the 28 teams vying for $7 million in prize money at Melbourne's Metropolitan Golf Club.
The top three pairings all shot 10-under-par on Thursday in the fourballs, or better ball, where both players have a ball but only the better score counts for each hole.
But no-one could go better than two under in the challenging conditions during the foursomes, or alternate shot, play where team-mates take it in turns to play the same ball.
Belgium's Thomas Pieters and Thomas Detry fired a 71 - one of only four teams to go sub-par - to be 10 under for the tournament alongside Korea's Byeong-hun and Kim Si-woo, who hit 72.
"It was really tough out there, but we kept it in play most of the time. A big miss off the tee around here and it's bogey or double bogey all the time," said Pieters.
"Thomas (Detry) holed out great from six or seven feet all day. And we made some really good recovery shots out of bunkers to save par."
The South Koreans were delighted with their level par round.
"It's such a tough format in this wind and rain, so I think we did well," said An, who plays on the PGA Tour.
The rain was non-stop all day and it was testimony to the draining power of the courses in Melbourne's famous sandbelt that golf was played at all.
Apart from surface water in bunkers testing the patience of players and officials, the Metropolitan stood up exceptionally well.
"It was unbelievable walking on the fairways out there," Detry said.
"It rained all day and all night and the course is in perfect condition. To be perfectly honest I didn’t think we would finish today and we did."
Joint overnight leaders and pre-tournament favourites Australia (Cameron Smith and Mark Leishman) are four off the pace while Danish defending champions Thorbjorn Olesen and Soren Kjeldsen) are six adrift.
"It was pretty brutal," said world No 21 Leishman.
"It wasn’t the start we would have liked but we fought back at the end. It was probably not a terrible round."
The American challenge is effectively over with Kyle Stanley and Matt Kuchar - both multiple winners on the PGA Tour - slumping to a 79 with six bogies on the back nine ruining their card, leaving them 11 behind the leaders.
Two-time major winner and former world number one Martin Kaymer and his German team-mate Maximilian Kieffer fared even worse with an 81.
Scores on Friday after the foursomes second round of the World Cup at the par-72 Metropolitan Golf Club in Melbourne (two days of fourballs and two days of foursomes in two-man teams):
134 - Belgium (Thomas Pieters/Thomas Detry) 63-71, South Korea (An Byeong-Hun/Kim Si-woo) 62-72
136 - Italy (Andrea Pavan/Renato Paratore) 65-71, India (Anirban Lahiri/Gaganjeet Bhullar) 64-72, Malaysia (Gavin Green/Ben Leong) 63-73, England (Tyrrell Hatton/Ian Poulter) 62-74
137 - Mexico (Abraham Ancer/Roberto Diaz) 67-70
138 - Scotland (Russell Knox/Martin Laird) 67-71, Australia (Mark Leishman/Cameron Smith) 62-76
139 - France (Alexander Levy/Michael Lorenzo-Vera) 66-73, Sweden (Alexander Bjork/Joakim Lagergren) 65-74
140 - Ireland (Shane Lowry/Paul Dunne) 64-76, Denmark (Thorbjorn Olesen/Soren Kjeldsen) 63-77
141 - Canada (Adam Hadwin/Nick Taylor) 68-73, Finland (Mikko Korhonen/Mikko Ilonen) 66-75, New Zealand (Ryan Fox/Mark Brown) 65-76
142 - Spain (Adrian Otaegui/Jorge Campillo) 68-74, China (Li Haotong/Wu Ashun) 66-76, South Africa (Dylan Frittelli/Erik van Rooyen) 66-76
143 - Wales (Stuart Manley/Bradley Dredge) 70-73
145 - Thailand (Kiradech Aphibarnrat/Prom Meesawat) 67-78, United States (Kyle Stanley/Matt Kuchar) 66-79, Japan (Satoshi Kodaira/Hideto Tanihara) 66-79
147 - Venezuela (Jhonattan Vegas/Joseph Naffah) 65-82
149 - Germany (Martin Kaymer/Maximilian Kieffer) 68-81
151 - Netherlands (Joost Luiten/Daan Huizing) 69-82
153 - Greece (Peter Karmis/Alexander Tranacher) 66-87
156 - Zimbabwe (Scott Vincent/Benjamin Follett-Smith) 72-84