Apple Inc. (Nasdaq:AAPL) has finally inked the long-awaited deal with China Mobile (NYSE:CHL), and Apple’s market share in China has already grown tremendously to 12 percent, making it the third-largest smartphone company in the county. This is all good news for Apple, but potentially disastrous for its competitor, the leading smartphone supplier in China – Samsung Electronics Co., Ltd. (KRX:005935).

"I think Samsung would be the biggest loser of the deal. There's no question Samsung will lose market share. Apple will take a large share of consumers who are willing to consider non-Chinese brands away from Samsung," Bob O'Donnell, founder and chief analyst, Technalysis, told CNBC on Monday.

The Apple-China Mobile deal, announced late on Sunday, had initially caused much excitement as it would mean the California-based electronics maker will have access to an additional 760 million customers from China Mobile, which is the largest Chinese mobile carrier by subscribers. But analysts have in recent weeks warned that the deal may not be as lucrative as previously thought.

Even so, with Apple’s popular iPhone models now available through all three of the major carriers – China Unicom Limited (NYSE:CHU) and China Telecom Corporation Limited (NYSE:CHA) already had agreements with Apple – the market could get rough for Samsung, whose market share was 17 percent in October, according to Counterpoint, a research agency.

"Apple iPhone 5s at all three carriers will for sure ignite a 'price war' boosting the overall iPhone 5s sales in China," said Tom Kang, research director at Counterpoint, adding that Apple and Samsung may be tied in terms of smartphone market share by January or February -- a peak shopping period in the mainland due to the Chinese New Year holidays, which begin at the end of January, according to the CNBC.

China Mobile will begin offering the iPhone 5s and 5c on Jan. 17. Pre-orders are available from Dec. 25. In addition, Apple is expected to launch the iPhone 6 in the coming year, which could bump up sales among China’s wealthier consumers and represent yet another product Samsung has to battle.

"There's high demand for large-screen phones in China. Samsung will have to counter Apple head on with a premium product, or trickle down to lower price points of around $200 to make up for that loss," said Kang.

Apple expects to sell between 15 and 25 million iPhones through China Mobile’s distribution channels in 2014, the CNBC reported.