Buick could be one of the most unlikely turnarounds in automotive history. When General Motors entered bankruptcy two years ago, the troubled car-making giant was pressured to abandon half of its North American brands. Most observers expected Buick to be one of the first to go. Somehow, though, the century-old marque survived. Now, it is in the running to become the best-selling luxury car brand in the U.S.

"The perception of Buick is out of whack," says Chris Perry, GM's North American marketing director.

Perhaps, but only a couple of years ago, Buick was clearly in dire straights. Once a badge to rival GM's flagship Cadillac, Buick had undergone decades of corporate neglect. Sales had plunged to barely a quarter of their peak by the time GM was forced into bankruptcy in 2009.

It might have made sense to close Buick, yet GM officials were reluctant to abandon it – not because if its presence in the domestic market, but due to a burgeoning reputation in a fast-growing region for car sales: Asia. "We kept Buick because of China," acknowledges Ed Wellburn, GM's global design director.

The brand's success in China was pure fluke. The last emperor was a Buick fan and, after World War II, his personal car landed in the hands Zhou Enlai, top lieutenant of China's postwar communist leader, Mao Zedong.

A little more than a decade ago, former GM chairman Jack Smith began negotiating with Chinese bureaucrats because the U.S. manufacturer was hoping to open a plant in Shanghai. GM wanted to build one of its mainstream global brands there, such as Chevrolet or Opel. The Chinese, however, were incensed. They wanted "the best," recalls a source who had been involved in the negotiations – and to them that meant Buick.

Today, China is playing a lead role in the development of the brand, although the new Buick Regal was heavily influenced by GM's European engineering operations. The results have been significant, with models such as the large LaCrosse sedan (unveiled at the Shanghai Auto Show, RIGHT) and Enclave SUV moving decidedly upmarket, with far more distinctive styling.

The consumer response has been equally apparent. Buick has gained sales for 17 straight months, picking up 73 percent year on year in February alone. So far this year the GM brand has outsold longtime U.S. luxury leader Lexus and missed out on topping BMW, the current sales champion, by just 800 vehicles. Significantly, around half of Buick's sales are coming from conquests of brands such as Lexus and Mercedes-Benz.

Buick's new-found momentum is gaining it respect inside GM as well. Within the next two years, the brand will have twice as many models as it did at the time that GM was filing for bankruptcy, and Buick marketing chief Craig Bierley hints that even more offerings are under study – essential, considering the product range expansion Buick's competitors are undergoing.

Keeping its momentum going all year won't be easy, analysts caution. However, even if Buick doesn't capture the top spot in the luxury market this year, it seems to be justifying the decision to keep the brand around.

Paul Eisenstein/Autocar