The loss continued the Australian's poor run at Wimbledon, where she has never advanced past the third round and where she has lost in the first round six times in her 12 appearances at the All England club.
Stosur recently split with her coach, Miles Maclagan, just seven months in their partnership. The 2011 U.S. Open champion hasn't reached the semifinals in any tournament since Hobart in January and in recent weeks lost on grass in the second round at Birmingham and the first round at Eastbourne.
Stosur said she won't be in a hurry to hire a new coach.
"By no means a rush ... I want to really take my time and think about it and make sure I'm doing the right thing," Stosur said.
"There's probably a handful of coaches that you might want to think about. They've probably all got jobs."
Wickmayer was watched by retired star Kim Clijsters, who has been working with the fellow Belgian player.
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