In an unusually bullish prediction, the company has said there is little chance that PS3 or Wii will be able to gain enough market share in the all-important fourth quarter to catch up.
Microsoft said it has received official data compiled by sales monitor GFK Chart-Track which shows that Xbox 360 outsold all consoles in the period between January and September.
Pawan Bhardwaj, product manager for Xbox Live, went on to tell CVG at an Xbox Music event on Monday that the group is "very, very confident" that it won't be overtaken during the holiday period.
"The data we have is for the January to September period, but I can absolutely assure you that the Xbox 360 will be the best-selling console for the calendar year," he said.
GFK Chart-Track has confirmed to CVG that it had provided the January-September data to Microsoft. A spokesperson for the sales monitor declined to comment on the predictions and said "we will reveal the year's best-selling hardware when the year is over".
Nintendo's transition from Wii to Wii U almost certainly means that neither console will outsell its rivals this calendar year.
Yet PlayStation UK is equally upbeat about its chances during Q4. Its new super-slim model, packaged with the JK Rowling-endorsed Wonderbook, is central to the company's hopes of attracting casual customers.
SCE UK boss Fergal Gara recently told CVG that the planets had aligned for an encouraging holiday sales season.
"If you look at the upcoming Christmas market, the Wii will be selling in very low volumes - it's on its way out - and the Wii U will arrive, but it will bring in a relatively small number of early adopter consumers. We see ourselves well positioned for the casual market who won't buy Wii U on day one.
"We've got a wow moment, we feel. I remember when people picked up the Wii controller for the first time, that was a big moment, it was a casual market breakthrough, but we thing we've got a casual market breakthrough as well with Wonderbook and the lowest priced PS3 yet."
On Monday, Microsoft outlined a fresh cross-media entertainment strategy. New features such as Xbox Music, SmartGlass, and Windows 8 will connect with each other and the 360 to provide a new kind of online entertainment ecosystem.