Apple slid down to fifth place in China's smartphone shipments, according to the latest data by Counterpoint Research.

Sale of iPhone units in the mainland plunged to 10.8 percent in May from 12 percent a year earlier. Meanwhile, its local rival Huawei experienced a significant lead with 17.3 percent, while Oppo nearly doubled its market share to 11 percent.

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Apple lagged behind domestic brands including Huawei, Vivo, Oppo, and Xiaomi. Together, these top four brands comprised more than half (53 percent) of the market share.

Apple has been dealing with a market slowdown in China, including Hong Kong and Taiwan. Its sale plummeted more than a quarter (26 percent) during the March quarter compared to 2015. Its Asia Pacific revenue also decreased to 25 percent year-over-year in the first quarter of the year.

According to 9to5 Mac, during the time, Apple has cited "significant channel reduction" and "currency weakness" as the reasons for the decrease of its profit in China.

Meanwhile, despite experiencing a slowdown and tough competition with local vendors, Apple CEO Tim Cook has publicly touted China's importance. However, the company has been facing a number of hurdles in China, resulting in several lawsuits and regulatory setbacks.

Earlier this year, Apple lost a trademark infringement case in a court ruling for its iPhone 6 and iPhone 6 Plus. Its iTunes Movies and iBooks services were also banned in April, just six months after they were granted permission. Furthermore, its app store and other services are also being regulated.

Tagsapple, Counterpoint Research, Huawei, Oppo, vivo, Xiaomi