Over 1.5 million Windows Phone 7 units have been shipped to shops since Microsoft launched the iPhone rival in October a start the US giant today described as "promising".
The Windows Phone 7 went on sale in Europe on 21st October and in the US on 8th November.
Before launch Microsoft proclaimed Xbox Live integration as the best thing about Windows Phone 7. 60 games were available at launch. Some, such as Zynga's Farmville, are aimed at the casual gaming audience. But others are clearly targeted at the Xbox's traditional fanbase, and have fancy 2D and 3D visuals.
Microsoft said shipments would have been higher had phone makers and carriers provided sufficient stock.
Achim Berg, Microsoft's vice president of business and marketing for Windows Phones, described the device as "a different kind of phone, fast and easy".
"Sales are ramping well as our reputation is growing for offering users a unique experience and are in line with our expectations especially when compared to other new platform introductions.
"We are pleased that phone manufacturers sold over 1.5 million phones in the first six weeks, which helps build customer momentum and retail presence.
"We know we have tough competition, and this is a completely new product. We're in the race it's not a sprint but we are certainly gaining momentum and we're in it for the long run."
Berg described Microsoft's sales expectations as "realistic", but refused to directly compare them with the competition - aka Apple's iPhone.
"It's a bit of apples and oranges comparison; our numbers are similar to the performance of other first generation mobile platforms. We introduced a new platform with Windows Phone 7, and when you do that it takes time to educate partners and consumers on what you're delivering, and drive awareness and interest in your new offering.
"We're comfortable with where we are, and we are here for the long run; Windows Phone 7 is just the beginning. Our opportunity is to make sure people get to play with a Windows Phone. Once they do, they love it. This is very important for us."
Microsoft is working on real-time phone-to-console gaming, likely initially through Wi-Fi, but the feature won't be ready for launch.