Home favourite Duan was the second highest seed in action on the opening day but again came unstuck against compatriot Wang as she crashed out 6-4 7-6 (7-3).
Wang has now beaten the 25-year-old in all six of their meetings, with Duan double-faulting five times in their hour-and-45-minute contest.
There were no such problems for fourth seed Luksika Kumkhum as she swept aside Chinese wildcard Wushuang Zheng 6-3 6-3 in her opener at the inaugural WTA 125K series hard-court event.
The Thai will take on Marina Melnikova or Gioia Barbieri next, while Belarus' Ilona Kremen remains on course for a second-round meeting with top seed Peng Shuai after disposing of Japan's Mari Tanaka in straight sets.
The 20-year-old won three quarters of her first service points on the way to a 6-1 6-1 win and awaits either Peng or Xinyun Han next.
Meanwhile, Thailand's Noppawan Lertcheewakarn avoided an upset against Chinese qualifier Hao Chen Tang.
With 194 places separating them in the rankings, Lertcheewakarn saved five of six break points to win through 6-2 6-4.
Australia's Monique Adamczak came up short in a hard-fought clash with Nastja Kolar of Slovenia - bowing out after a 7-6 (7-5) 6-3 defeat, while Lin Zhu was the second Chinese to progress as she beat past Su Jeong Jang of South Korea 6-3 6-4.