“Mario Kart 8” continues to top the game charts, selling more than 470,000 units last month on the Wii U. Though Ubisoft’s open world action-adventure game “Watch Dogs” actually outsold the Nintendo racer, “Mario Kart 8” sold the most games on a single platform, which means it has moved approximately 870,000 copies in the United States alone.

“These results reinforce the power of the ‘Mario Kart’ franchise and speak to a bright future for the Wii U platform,” Scott Moffitt, Nintendo of America’s executive vice president of sales & marketing, told Forbes last week. “History has shown that ‘Mario Kart’ games tend to have an extremely long tail. We fully expect ‘Mario Kart 8’ to continue to drive momentum for our hardware and software business through the holidays and into the foreseeable future.”

According to Nintendo’s 74th Annual Shareholder’s Meeting in Japan last month, “Mario Kart 8” has sold 2 million copies worldwide, also boosting Wii U sales more than 90 percent compared to May of last year.  It became the Wii U’s fastest-selling game with more than 1.2 million units sold worldwide within less than two weeks of its launch.

On June 2, U.K. market research and media sale monitoring company GFK Chart-Track said the game had boosted Wii U sales by 666 percent, with 82 percent of that coming from the “Mario Kart 8” bundle.

The eighth main installment in the series also boosted Wii U console sales more than first-person shooter “Titanfall” boosted Xbox One sales following its release in March and more than action-adventure game “inFAMOUS: Second Son” increased PlayStation 4 sales after its March 21 release date.

Since the release of “Mario Kart 8,” the Wii U has even outsold the Xbox One. As of June 14, Wii U’s global install base was at 6.4 million. The Xbox One was at 4.6 million and the PS4 was at 8.1 million. However, the PS4 and Xbox One launched last November, while the Wii U hit shelves almost a year earlier in 2012.