Ireland's Leona Maguire fell four shots off the pace after a disappointing second round in the Omega Dubai Moonlight Classic.
Maguire held a two-shot overnight lead following a course-record 64 on day one at Emirates Golf Club but struggled to a 75 on Thursday to post a halfway total of five under par.
Spain's Nuria Iturrios, who claimed her second Lalla Meryem Cup title in Morocco at the weekend, shares the lead on nine under with German rookie Esther Henseleit after the pair carded second rounds of 68 and 66 respectively.
Maguire fired nine birdies in her opening round but failed to register any on day two and was disappointed to make a double bogey on the seventh, her 16th hole of the day, after a difference of opinion with her caddie over club selection.
"I didn't give myself many chances today," the 24-year-old said. "On seven I wanted to hit 7-wood, my caddie wanted me to hit an iron and I hit an iron in the water, which was quite annoying to finish with.
"I didn't give myself enough chances and didn't hole any putts, so no birdies today. I need to play a lot better tomorrow and hit my irons better to give myself some more chances."
England's Hannah Burke is six shots off the pace after a bogey-free 69, with Scotland's Kylie Henry a stroke further back following a 73.