After launching late last week, Mario Kart 8 has become the Wii U's fastest-selling game ever with more than 1.2 million units already sold worldwide, Nintendo announced today. This number is according to the company's internal sales data and accounts for sales in the Americas, Europe, and Japan.

Nintendo made no mention of how the game has impacted sales of the beleaguered Wii U console itself, although UK retail tracking group GFK Chart-Track announced on its own today that Wii U hardware had seen a 666 percent sales boost in the UK over the weekend. No specific sales figures were shared in the GFK report, but 82 percent of hardware sales were said to be the Mario Kart 8 bundle.

Nintendo had been hoping that Mario Kart 8 would serve as a "catalyst" for sales of the Wii U, which has struggled to live up to expectations thus far. As of March 31, only 6.17 million Wii U systems had been sold worldwide since its launch in November 2012, a number that is well behind the 9 million it expected to sell between April 2013 and March 2014.

"The early response to Mario Kart 8 demonstrates that the best days for Wii U are still ahead," said Nintendo of America president Reggie Fils-Aime as part of today's announcement. "This year’s E3 is just days away, and it will be all about the future games for Nintendo platforms. This milestone is a great place to start!"

The Mario Kart games have routinely been among Nintendo's best-selling titles; according to Nintendo, series sales eclipsed 100 million as of the end of March. Mario Kart 8's sales make it one of the best-selling games on Wii U; it's roughly on par with the 1.22 million copies of The Legend of Zelda: The Wind Waker HD sold, but for now trails the platform's top sellers, New Super Mario Bros. U (4.16 million), Nintendo Land (3.09 million), and Super Mario 3D World (2.17 million).

Along with the new Super Smash Bros., Mario Kart 8 was one of the two major Wii U releases on the horizon from Nintendo. The game features high-definition graphics for the first time in series history, as well as improved online play and a new Mario Kart TV replay feature (providing us with video of phenomenal moments such as this). Gamers who buy the game and register it on Club Nintendo by the end of July will receive a free digital copy of select Wii U games, while everyone is free to be creeped out by the live-action Mario being used to advertise the game's Mercedes Benz GLA crossover in Japan.

For more on Mario Kart 8, check out GameSpot's review.

If you picked up Mario Kart 8 this weekend, were you already a Wii U owner, or was this the game to finally get you to pick one up?