Apple Inc said it sold more than two million of its new iPhone 5 in China during the three days after its launch there on Friday, marking China’s best-selling iPhone rollout ever.

But the highly anticipated release in China, Apple’s second-biggest market, has not eased worries about stiffer competition in smartphones that are driving a slide in the share price of the world’s most valuable technology company.

Apple shares fell 3.8 per cent on Friday to $509.79 after the iPhone 5′s China debut, while Citi Research downgraded Apple’s stock late on Sunday to “neutral” from “buy” and lowered Apple’s price target to $575 from $675, citing diminishing hype around the iPhone 5 and improving competition in smartphones.

Apple’s latest iPhone made its global debut with a launch in the United States and 30 other countries in September, selling more than 5 million in its first three days on the market.“Customer response to iPhone 5 in China has been incredible, setting a new record with the best first weekend sales ever in China,” Apple Chief Executive Tim Cook said in a statement.

This is the first time Apple has announced China sales numbers for the iPhone.Analysts say Apple’s longer-term outlook in the China market, however, may hinge on expanding its partners in that country to include China Mobile Ltd, the country’s top telecoms carrier.