As Tesla’s U.S. sales slow, the growing China market is increasingly playing a more important role in its global sales as the American electric-car maker inches toward opening its Shanghai factory.

Tesla’s third-quarter revenue in China surged 64% year-on-year to $669 million, a stark contrast to the U.S., where its sales were down $2 billion to $3.1 billion, according to a regulatory filing.

Tesla racked up $6.3 billion in total revenue in the third quarter, according to the filing, with the U.S. remaining the biggest source of revenue.

Its Shanghai factory has started producing electric vehicles on a trial basis, and has been described by founder Elon Musk as a “template” for the company’s future growth. The factory is set to expand Tesla’s production capacity by 500,000 units by June 2020.

On Tuesday, Tesla said that it had expanded its fast-charging network in the Chinese mainland to include 2,000 charging stations.

The company has so far placed its “Superchargers” in more than 130 Chinese cities, the company said.