Tesla’s European sales fell over 10% in September, while those of rival BYD surged nearly 400% from last year as the Chinese electric vehicle maker gained more market share in the region.

Tesla registrations in the Europe, the EFTA, and the UK regions fell 10.5% year-on-year to 39,837 units in September, data from the European Automobile Manufacturers’ Association (ACEA) showed on Tuesday. 

The EV maker’s market share also shrank to 3.2% from 4.0%. But sales did increase sharply from the prior month’s reading of 14,831 units. 

BYD’s new car registrations surged 398% to 24,963 vehicles in September, while its market share jumped to 2% from 0.4%. The big percentage jump was driven largely by BYD having a relatively limited presence in Europe last year, which made for a smaller comparative figure. 

BYD’s September sales also picked up sharply from the 11,455 units sold in the prior month. 

Overall European new car registrations grew 10.7% y-o-y to 1.24 million units, amid increasing adoption of EVs and hybrid class vehicles. Petrol and diesel vehicle sales both declined in the region. 

Hybrid EVs commanded the biggest market share in Europe as of September, at 34.7%, followed by petrol, at 27.7%. Battery EVs, in which Tesla is the largest player, held a 16.1% market share.

September’s data showed Tesla’s European sales continuing to decline, albeit at a smaller pace than that seen in earlier months. The EV maker is grappling with heightened competition in the region, especially from more affordable and comparable alternatives from BYD.

A host of European automakers were also seen rolling out new EV offerings this year, while Tesla’s brand image in Europe remained weak amid public disdain towards CEO Elon Musk. 

Tesla clocked record-high deliveries during the September quarter, although analysts attributed the trend largely to customers bringing forward their purchases before the expiration of U.S. EV tax credits.

The company’s third-quarter profit disappointed markets, as profit margins remained slim and faced more pressure from Tesla’s pivot into artificial intelligence technology and robotics. 

BYD outsold Tesla in Europe in several months this year, as the Chinese EV maker ramped up its plans for international expansion. Both companies are also embroiled in a bitter price war in major market China, which was seen severely crimping their margins in recent quarters.