TMTPOST -- Apple experienced an 18.2% decline in iPhone sales in China during the December quarter, according to independent research, marking a significant setback in its largest market outside the United States. The company’s flagship smartphones, which held the top spot in China a year ago, were overtaken by Huawei Technologies Co., according to Counterpoint Research. Apple fell to third place in the Chinese smartphone market over the three-month period, capturing about 16% of the market share. The downturn in China contributed to a 5% global drop in iPhone sales during the crucial holiday shopping season, underscoring challenges for Apple as it faces intensifying competition in the world's largest smartphone market.