The latest research data from Gartner shows Apple's first year-over-year decline in iPhone sales coincided with a reduced share of the global smartphone market. Although the global smartphone market grew by just 3.9 percent year-over-year, Apple was notable for going backwards. Although holding its position as the number two smartphone maker in the world, its market share slid from 17.9 percent to 14.9 percent. Whatever the exact cause of the decline, Gartner's data shows that Apple is not immune to the increasing rise of Chinese smartphone makers.

Like Apple, Samsung's market share also took a backward step, although it was not as sharp as Apple's. Samsung's share declined year-over-year by 0.9 percent to 23.2 percent, down from 24.1 percent. Chinese makers, however, generally enjoyed a promising quarter. Huawei was the biggest winner for the quarter, with an 8.3 percent market share, up from 5.4 percent, with Oppo also making a gain. It held a 4.6 percent share of the market for the March quarter, up from two percent during the same period last year. Xiaomi held steady with a 4.3 percent share.

"In a slowing smartphone market, where large vendors are experiencing growth saturation, emerging brands are disrupting existing brands' long-standing business models to increase their share," said Anshul Gupta, research director at Gartner. "With such changing smartphone market dynamics, Chinese brands are emerging as the new top global brands. Two Chinese brands ranked within the top five worldwide smartphone vendors in the first quarter of 2015, and represented 11 percent of the market."

Apple has forecast another difficult quarter ahead, placing at least some of the blame for its current challenges on the strong US dollar. With the dollar stronger against numerous currencies, Apple has put greater emphasis on retaining its overall margins by moving the pricing of its products up in line with currency movements in those countries and markets, rather than absorbing any of the costs by either keeping its pricing stable in global markets, or lowering them to help stimulate sales.