Samsung Electronics Co.'s Galaxy S4 was dethroned by Apple Inc.'s iPhone 5S, which became the best-selling smartphone in the world in September, data showed on Wednesday. According to the data compiled by Hong Kong-based Counterpoint Technology Market Research, Apple's iPhone 5S became the bestselling phone last month in just 10 days of its release, ending the Galaxy S4's several month reign. Samsung took the No. 1 position in the premium smartphone market of phones above the US$400 price point in May this year, displacing Apple Inc. for the first time.