Helped by an eagle at the par-five ninth - his final hole at the Yalong Bay Golf Club in Sanya - the World No 7 overcame a stuttering first nine holes with a stunning second-loop of 30 and a 7-under round that took his halfway tally to 15-under-par.

New Zealander Campbell, the 2005 US Open champion, had an eagle three of his own at the 13th, but his round of 68 left him on 12 under in a two-way tie with overnight leader Lu Wen-teh.

After opening with a blistering nine-under-par 63, Lu cooled off with a 69 to drop back into joint second place with Campbell

Dubai-based Scotsman Ross Bain, fighting to save his Asian Tour card, added a 67 to his opening 68 to move into a tie for fourth on nine under with Englishman Yasir Ali and Australian Marcus Both.

Another Scot, Simon Dunn, is two shots further back after rounds of 68 and 69.

Goosen, who has yet to win anywhere this year, started his round sluggishly with three birdies against bogeys on the 16th and 18th, but when he turned everything changed as he set off on another master-class performance reminiscent of the one here last year that earned him his six-shot triumph.

He signed off in style, smashing a glorious three iron to within three feet at the par five ninth hole for an easy eagle.

"It was an up and down round. The first six holes, I played extremely well. I should have been six under, but I couldn't make a putt.

"Then I hit it into the water for the second day running on 16 and that kind of stopped the round for the next five or six holes.

"I set a goal of finishing at 11-under-par as things weren't going my way, but then I made good birdies on number three and four which settled me down and on the last few holes and it all happened,"

"I think I can go lower if I play the par fives better.

I have a chance to get to 22-under," said Goosen, a two time US Masters champion who triumphed last year with a 22-under-par total.

Campbell is hoping to avenge last year's loss to Goosen but knows he'll have to keep down mistakes.

"I played nicely all day today apart from the last two holes.

"It's a shame. Bogeying the 17 and 18 always leaves a bad taste in the mouth but there are still two rounds to go. Hopefully I can make progress by shooting low tomorrow," he added.

LEADING SECOND ROUND SCORES

129 - Retief Goosen (RSA) 64-65

132 - Michael Campbell (NZL) 64-68, Lu Wen-teh (TPE) 63-69

135 - Marcus Both (AUS) 70-65, Ross Bain (SCO) 68-67, Yasin Ali (ENG) 66-69

137 - Simon Dunn (SCO) 68-69

138 - Arjun Singh (IND) 70-68, Scott Strange (AUS) 67-71, Huang Ming-jie (CHN) 67-71, Anthony Kang (USA) 70-68, Danny Chia (MAS) 67-71

139 - Lin Wen-tang (TPE) 68-71, Kane Webber (AUS) 70-69

140 - Li Chao (CHN) 70-70, Chinarat Phadungsil (THA) 72-68, Lu Wei-lan (TPE) 70-70, Gerald Rosales (PHI) 68-72, Adam Blyth (AUS) 69-71, Tony Lascuna (PHI) 68-72, Suk Jong-yul (KOR) 68-72, Gurbaaz Mann (IND) 74-66

141 - Thammanoon Srirot (THA) 73-68, Juvic Pagunsan (PHI) 72-69, David Freeman (HKG) 71-70, Prom Meesawat (THA) 72-69, Wu As-hun [A] (CHN) 70-71, Chapchai Nirat (THA) 73-68, Adam Le Vesconte (AUS) 68-73, Kevin Chun (NZL) 72-69, Digvijay Singh (IND) 70-71, Lam Chih Bing (SIN) 72-69

142 - Chen Tze-chung (TPE) 70-72, Simon Griffiths (ENG) 73-69, Michael Wright (AUS) 70-72, Chan Song (KOR) 72-70, Somkiat Srisanga (THA) 68-74, Frankie Minoza (PHI) 73-69, Jason King (AUS) 74-68, Brad Iles (NZL) 70-72, Liao Gui-ming (CHN) 72-70

143 - Zhang Lian-Wei (CHN) 72-71, Unho Park (AUS) 72-71, Corey Harris (USA) 73-70, Gary Rusnak (USA) 69-74, Andy Martin (AUS) 71-72, Gavin Flint (AUS) 72-71, Ari Savolainen (FIN) 72-71, Garth Mulroy (RSA) 71-72