Smartphone maker Xiaomi Corp on Wednesday debuted its flagship handset and pledged to open 300 retail stores to fight against Huawei Technologies Co Ltd, which is threatening its leading position in China.

Lei Jun, CEO and co-founder of the Beijing-based Xiaomi, said the new device and offline sales plan will let the challengers know who is the boss on the market.

"We are sorry other vendors were left disappointed," Lei said on Wednesday at the launch. He was obviously mocking Huawei's 2015 plan to get on top of Xiaomi in Chinese market by the year-end. Xiaomi ended up shipping 2 million devices more than Huawei did last year, according to research firm International Data Corp.