Microsoft announced today that Forza Horizon 4 has reached 2 million players. The open-world racing game came out on October 2 for Xbox One and PC.

This sales success is important for Microsoft. Forza Horizon 4 is the biggest console exclusive that Xbox One has for the rest of the year. It could help drive sales of systems during the lucrative holiday season.

Forza Horizon 4 is also available in the Xbox Game Pass, a $10 a month subscription service that gives owners access to a library of games. The popularity of Forza Horizon 4 can boost subscription numbers to the service.

Xbox Game Pass is also why Microsoft is touting total players instead of games sold. Those 2 million players include those paying the monthly Xbox Game Pass subscription.

Microsoft also notes that Forza Horizon 4 has become the highest-rated Xbox exclusive of this console generation. Our own review calls it the best entry in the Forza Horizon series.