The 22-year-old was beaten 6-3 6-4 by former Wimbledon champion Marketa Vondrousova to add to her losses to Iga Swiatek in the third round of the Australian Open and to Cristina Bucsa in Singapore last week.
Originally given a wild card into qualifying, Raducanu was bumped up to the main draw and handed a tricky opener against Czech Vondrousova, who has struggled with injury since last summer.
Raducanu made a strong start but fell away badly during the latter stages of the opening set, while Vondrousova also edged a close second.
Raducanu is travelling with only fitness trainer Yutaka Nakamura following former coach Nick Cavaday's decision to step down for health reasons, but she did have another old childhood mentor, Roman Kelecic, in her corner.
Kelecic is now based in Dubai but has been helping out Raducanu this week, and initially the signs were positive as the British No 2 took advantage of a shaky start on serve from her opponent to move into a 3-1 lead.
But a long Raducanu service game that followed proved the turning point, with Vondrousova eventually breaking and then reeling off five games in a row.
Raducanu seemed to be struggling with discomfort in her neck and made a succession of errors, but she regrouped at the start of the second set and applied strong pressure to the Vondrousova serve.
She could not force a break, though, and was staring at defeat after dropping serve herself in the eighth game.
Raducanu broke back immediately but was unable to hold her own delivery as Vondrousova clinched victory.
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