London (CNN Business) Qatar Airways is buying into the one market no major airline can ignore: mainland China.

The state-owned Gulf airline said Wednesday that it has acquired 5% of China Southern Airlines ( ZNH ), the country's largest carrier. US rivals American Airlines ( AAL ) and Delta ( DAL ) already have stakes in China Southern and China Eastern ( CEA ), respectively.

Qatar Airways said it acquired its stake by purchasing China Southern shares on the Hong Kong and Shanghai stock markets. It's the first major investment in mainland China by Qatar Airways.

Akbar Al Baker, the CEO of Qatar Airways, said the investment offered "massive potential."

"China Southern Airlines is one of the most prestigious airlines in the Chinese domestic market and an important market player in the world," Al Baker said in a statement.