The U.S. tech giant's chief competitor in China in premium smartphones, Huawei, saw unit sales rise by 64% in the period, according to the report.
Apple's share of the Chinese smartphone market dropped to 15.7%, putting it in fourth place, compared with second place in the same period of 2023 when it accounted for 19% of the market.
Huawei rose to second place as its market share expanded to 16.5% from 9.4% a year earlier.
The overall smartphone market in China shrank 7%, the report said.
Apple "faced stiff competition at the high end from a resurgent Huawei while getting squeezed in the middle on aggressive pricing from the likes of OPPO, Vivo and Xiaomi,” said Counterpoint's senior analyst Mengmeng Zhang.
It had already offered iPhone discounts of up to 500 yuan on its official sites last month.
Huawei has seen a resurgence in its premium smartphone sales since it released its Mate 60 series in August after struggling for years with U.S. restrictions on the exports of key components to the company.
Honor, the smartphone brand spun off from Huawei in 2020, was the only other top-five brand to see unit sales increase during the first six weeks of the year, up 2%. Chinese brands Vivo, Xiaomi and Oppo dropped 15%, 7% and 29% respectively.
