Coming into the tournament, World No.181 Duan had lost her past three matches but flew out of the traps against Date-Krumm, breaking early on to establish a 3-1 lead.
These early inroads proved the difference in a first set where both players struggled to hold onto their serve. After taking the opener, Duan continued her dominance of the Date-Krumm delivery, breaking three more times as she calmly closed out a 63 62 win.
In the pick of the opening round encounters No.2 seed Wickmayer overcame Yaroslava Shvedova, 75 62.
Just 12 months ago, Shvedova was on the cusp of breaking into the Top 20, but a difficult year has seen her slip down to No.82 in the rankings. And despite bright starts in both sets, she was unable to reverse this trend against Wickmayer, dropping the final five games as she slumped to her seventh defeat in the past 10 matches.
Zhang Shuai, the No.3 seed, continued her excellent run of form with a dominant win over qualifier Nicha Lertpitaksinchai. Hitting seven aces and winning nearly three quarters of the points, Zhang required just an hour to record her 15th win since the US Open, 63 60.