“Mario Kart 8” launched Friday for Nintendo Co. Ltd.’s (TYO:7974) Wii U, and sales of the long-awaited racer are already moving Wii U consoles off shelves in the U.K.

“Mario Kart 8” sales came in second only to action-adventure title “Watch Dogs,” which launched May 27 for the Xbox One, Xbox 360, PS3, PS4 and PC.

“While there is no contest for top spot, Wii U exclusive ‘Mario Kart 8’ races comfortably into second place. The much-loved series makes an impressive debut becoming the bestselling week 1 for any Wii U title since launch and the second-best in the Mario Kart series ever,” market research and video, music and software sale monitoring company GFK Chart-Track said Monday.

“‘Mario Kart 8,’ like ‘Watch Dogs,’ also launches an official hardware bundle this week boosting the sales of Wii U hardware by a whopping 666 percent, of which 82 percent are the Mario Kart 8 Bundle,” the company added.

The game features 32 courses, along with two separate versions of the popular Rainbow Road track. Developers emphasized how much work went into the highly anticipated title, the first installment in the franchise since 2011, with the exception of the arcade version, which Nintendo launched in 2013.

"Game balance is a really important element of Mario Kart that we look very closely at and place a lot of value on," game producer Hideki Konno told Gamespot on April 3. "From the time we start working on development, thousands of times, maybe even tens of thousands of times, we adjust that balance when we're playing. At the end, we come up with what we hope and feel is a really good balance. It's our strong hope that folks would want to play with the items as we have balanced them."

“Mario Kart 8” launched May 30 in the U.S., Europe and Australia. The title is the eighth installment in the main series. Unveiled at E3 last year, the game received positive reviews. On Feb. 15, “Mario Kart 8” ranked No. 1 on the preorder gaming list on Amazon Japan and ninth on Amazon UK. By February, “Mario Kart 8” was outselling the PS4 on Amazon’s Japan site. Demand was already high for “Mario Kart 8” months before Nintendo launched the title. Many believed the game would help Wii U sales, but Nintendo hasn’t revealed any exact sales figures since "Mario Kart 8's" release on Friday.