The best-selling third-party Switch game so far is Mario + Rabbids: Kingdom Battles.
Eurogamer confirmed this via UK charts company GfK Chart-Track and NPD, which monitors sales in North America and Australia. There is also the suggestion that it may have outsold some Nintendo titles, such as 1-2 Switch or Arms.
It means that Mario + Rabbids: Kingdom Battle has accomplished more than other third-party titles within just one month, having launched at the end of August. Titles such as Super Bomberman R and Puyo Puyo Tetris have been available since Switch launched back in March.
The Ubisoft crossover's success is perhaps not too surprising. While developed by a third party, it is still headlined by Mario, and may be perceived by some consumers as an official Nintendo title. Historically, Nintendo's first-party franchises have always dominated sales on its platforms.
It's also worth noting that third-party support so far for Switch has been somewhat muted, with only a handful of titles released to date. This is about to change: Bethesda will deliver Skyrim and Doom for Switch by the end of the year, with Wolfenstein II to follow in early 2018, while Rockstar Games has confirmed a Switch version of critical hit LA Noire.
While Nintendo has dominated Switch sales at retail with a new release almost every month, third-parties have fared well digitially - particularly in the indie space. Numerous studios have confirmed the Switch version of their games have outsold all other platforms, sometimes combined.
Ubisoft also has a history of faring well on Nintendo platforms. It was the most successful third-party publisher on the Wii, thanks primarily to the success of the Just Dance series.
Mario + Rabbids: Kingdom Battle has yet to make it to shelves in the East, with Nintendo handling publishing duties itself in Japan and South Korea.
Earlier this year, we spoke to creator Davide Soliani and composer Grant Kirkhope about how this seemingly bizarre mash-up came to be.