Two weeks after China's Li Na wowed the world by winning the French Open and becoming the first Asian to take but a Grand Slam event, the tennis star's signature was on a contract with Mercedes-Benz to do celebrity endorsements for its cars in China.

The three-year contract, reportedly worth more than US$1.5 million, is an advertising coup linking one of the world's prestige auto brands with the current sweetheart of the world's biggest auto market.

Mercedes-Benz surprised the public with the speed of its market response and its strong business acumen. But beyond that, the deal is another sign that auto makers in China are wedded to the strategy of using celebrity endorsements and other high-profile campaigns to go after a prime market: young people with cash to spare and a flair for luxury goods.

"Mercedes-Benz's decision to use Li Na is a very good one," said Tom Doctoroff, chief executive officer of advertising firm JWT in China. "Li Na can be an icon because she creates a new definition of Chinese excellence, and I think a lot of young Chinese respect her independent spirit."

He added, "The emerging middle market in China is young, and Mercedes-Benz is making its pitch more contemporary because that's what it needs to sell cars."

Of course, there's nothing new about the cozy relationship between sports and business. One only has to see the name brands on stadium billboards and the logos on the clothing of sports stars to know that endorsements go hand-in-hand with the victory cup.

Li has reportedly agreed to lend her name to endorsements for a range of products, including Nike and Rolex brands.

Other high-profile Chinese sports stars, including badminton player Lin Dan, have signed similar advertising deals with Wrigley's chewing gum. And the marketing doesn't end with sports. Celebrities such as actor and director Jiang Wen have also jumped on the endorsement bandwagon, lending their names to advertisements for cars, clothing and even websites.

According to Mercedes-Benz's contract with Li Na, Li will also be the brand ambassador for Mercedes-Benz "Swing for the Stars" Junior Tennis Development Program, which is aimed at nurturing a new generation of talent.

Mao Jingbo, vice president of marketing at Mercedes-Benz (China) Ltd, said the company's choice of brand ambassadors was not a fluke decision. According to her, Mercedes-Benz has been an active supporter of tennis in China for more than 15 years, and Li Na's involvement in junior tennis development program dates back to 2008.

"With our dedication to supporting tennis in China, Li Na was a natural choice because her passion for the sport and her determination to win are truly an inspiration to tennis enthusiasts and reflect Mercedes-Benz's 'the best or nothing' philosophy," she told Shanghai Daily.

Celebrity endorsements are a popular marketing tool everywhere in the world, but the notion of brand ambassadors is particular powerful in China.

"As a developing market, Chinese consumers still show a certain lack of discrimination," said Saurabh Sharma, a planning partner with Ogilvy & Mather Beijing. "That makes celebrities very powerful in their ability to help people try new products and consume with greater confidence."

Doctoroff also noted that most Chinese consumers see brands as a way to express their own identities. "So it's very important to have the right celebrity that fits with business objectives," he said.

Celebrity endorsements, while they come at a pricey costs, don't automatically guarantee higher sales.

In 2005, VW's Chinese venture FAW VW reportedly signed a 10 million yuan (US$ 1.6 million) contract with kung fu film star Jackie Chan to be the brand ambassador for its multi-purpose vehicle Caddy.

By the end of that year, Caddy reported annual sales of only 1,000 vehicles. The model was finally scrapped in August 2007, even though Chen's contract was still in force.

A more recent example was Lionel Messi, an Argentine football star who signed up to plug domestic carmaker Chery's premier Riich G5 model for a cool 5 million euros (US$7 million). Television ads featuring Messi appeared last year.

But consumers failed to see any link between the football superstar and Chery's first high-end model car. The Riich G5 proved to be a flop.

China's car market is large and growing rapidly. Competition is forcing automakers to try every approach they can think of to promote their brands and win customers.

Besides celebrity endorsements, digital marketing is fast becoming a popular strategy that aims directly at the Internet zeal of China's younger generation. Cadillac and other premium car brands have begun electronic direct-mail advertising in China, plugging their brands through online microblogs and Internet portals.

Cadillac, for example, is touting its brand with associations to the famous Route 66 highway in the US. The ads introduce the cultural and historical highlights of the road that connects Los Angeles and Chicago, and was once referred to as "the Main Street of America" by humorist Will Rogers.

"The campaign mainly aims to elicit an emotional response in consumers and strengthen the brand spirit," said Alix Liu, brand director of Cadillac at Shanghai General Motors.

The luxury car maker has also developed a micro movie for the campaign, which has attracted more than 200 million online clicks and has been re-tweeted over 260,000 times on Weibo.com, China's version of Twitter.

JWT's Doctoroff said car makers need to expand their use of channels such as online car clubs and social networks in the future besides simply spreading informations.

"The digital age allows people not only look at the brands but also to engage with the brands," he said. "By doing that, a company can encourage purchases and instill brand loyalty."

But car makers need to proceed smartly, Doctoroff warned. "It's very important to target opinion leaders online with content and allow them to spread to the world," he said.

As an advertising veteran of more than 13 years in China, Doctoroff admitted that many local Chinese local companies are still pretty naive when it comes to executing marketing concepts. Still, that trend is changing, and nowadays more than 40 percent of JWT's Chinese revenue comes from domestic companies.

He said Chinese carmakers can't move up into premium classes or expand abroad without more sophisticated marketing campaigns.

"Marketing is all about creating value perceptions so that you can increase your prices and increase your margins," Doctoroff said. "The only way to compete abroad is to have a premium marketing concept."