Taiwan's Wang Ter-chang and Lu Wei-lan were a stroke behind the leaders. Defending champion Jason Knutzon of United States was at 67 with Thailand's Pronsakon Tipsanit, South Korea's Suk Jong-yol and Australia's Jason Dawes, Terry Pilkadaris and Jarrod Lyle.
Knutzon was excited about outscoring Couples, the 1992 Masters champ.
'I grew up as a Fred Couples fan, so it was a pleasure to play with him,' Knutzon said.
Both, winner of the 2003 Sanya Open in China, had eight birdies and one double bogey. Zheng, whose highest finish on the Asian tour is 23rd place, birdied three consecutive holes on the front nine and shot four more and a bogey on the back nine.
China's Zhang Lianwei, the tournament winner in 2001 and 2002, was at 69. Thailand's Thaworn Wiratchant, hoping to become the top money winner on the Asian tour, shot a 71.
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