Cincinnati: Kei Nishikori lost to fellow Japanese Yoshihito Nishioka 7-6 (2), 6-4 on Wednesday in the second round of the ATP Cincinnati Masters.The sixth seed went down to his 77th-ranked compatriot, who came through qualifying, in just over 90 minutes.
Nishikori has never advanced beyond the third round at the US Open warm-up event.
Simona Halep fought back from a set down to defeat Russia's Ekaterina Alexandrova 3-6, 7-5, 6-4 in her Cincinnati WTA opener on Wednesday.
Wimbledon champion Halep, seeded four, earned a late break in the penultimate game of the final set to reach the third round after two hours of action.Halep has finished runner-up in Cincinnati three times, last reaching the final a year ago against Kiki Bertens.
In the next round, the 27-year-old Romanian, who retired injured from her Toronto quarter-final against Czech qualifier Marie Bouzkova last week, will next face either Madison Keys of the United States or Russia's Daria Kasatkina.