Thailand's rising tennis star Luksika Kumkhum lost to Mona Barthel of Germany 6-4, 3-6, 4-6 in the women's singles second round of the Australian Open on Wednesday.
The 20-year-old Thai, who upset 2011 Wimbledon champion Petra Kvitova of the Czech Republic in the first round, received treatment on her back several times during the second set.
World No.39 Barthel will meet 28th seed Flavia Pennetta of Italy in the third round. The Italian beat Monica Puig of Puerto Rico 6-3, 6-4.
Tamarine Tanasugarn, the only other Thai player in the main draw, and China's Zheng Saisai lost to 13th seeds Chan Hao-ching of Taiwan and Liezel Huber of the US 3-6, 3-6 in the first round of the women's doubles.