Diablo III was purchased an incredible 3.5 million times in the first 24 hours that it was available, becoming the fastest selling PC game ever in the process.
After a week, 6.3 million were playing, said Blizzard.
Those figures excluded World of Warcraft Annual Pass owners who got a copy for free. If they are counted, the day one total would be 4.7 million gamers playing on May 15.
Also excluded were players logging on in internet gaming rooms in Korea, where on May 22 the game had jumped to the top of the most-played chart and took a 39 per cent share of players.
"We're definitely thrilled that so many people around the world were excited to pick up their copy of Diablo III and jump in the moment it went live," said Blizzard CEO Mike Morhaime.
"We also regret that our preparations were not enough to ensure everyone had a seamless experience when they did so. I want to reaffirm our commitment to make sure the millions of Diablo III players out there have a great experience with the game moving forward, and I also want to thank them for their ongoing support."
The sales were one thing, but player feedback was just as important, said Morhaime.
"We're especially proud of the gameplay feedback we've received from players worldwide. We're pleased that Diablo III has lived up to players' high expectations, and we're looking forward to welcoming more players into Sanctuary in the days ahead."
Amazon's director of video games, John Love, confirmed that the game had set records for that site too.
"Not only did Diablo III break the record for most pre-ordered PC game of all time on Amazon.com, but it also shattered the record for best day-one sales for any PC game ever."