Two and a half years ago, Microsoft (NASDAQ:MSFT) set out on a goal. The software giant knew that it needed to revamp its mobile offerings, and to that end it shifted its focus away from its Windows Mobile platform in favor of Windows Phone. The company wanted to become the No. 3 operating system platform, which in no uncertain terms meant overtaking BlackBerry (NYSE:BB).

On a worldwide basis, Microsoft accomplished exactly that in the first quarter. IDC's estimates pegged Microsoft's global market share a hair above BlackBerry's for the first time ever. Most of Windows Phone's gains are attributable directly to Nokia and its Lumia lineup, which now comprises four out of every five Windows Phones sold throughout the world.

Well, Kantar Worldpanel ComTech has just released its latest digits on the important U.S. smartphone market, and the estimates show that Microsoft is now crushing BlackBerry.

U.S. Smartphone Share

3 Months Ending April 2012

3 Months Ending April 2013

BlackBerry

5.3%

0.7%

Windows

3.8%

5.6%

Source: Kantar Worldpanel ComTech.

Over the course of a year, Microsoft has grown its domestic market share respectably while BlackBerry continues to slide, now claiming less than 1%. These figures are particularly notable since they include the U.S. launch of the Z10, which occurred in late March, albeit the Z10 wasn't on sale for the entire quarter in question.

BlackBerry modestly increased its position at No. 2 carrier AT&T, but lost a lot of traction at the No. 1 carrier Verizon Wireless. Verizon is giving Windows Phone another shot, as Big Red likes to root for the underdogs in the hopes that the ensuing competition brings down subsidy costs.

The next quarter's figures will be more telling of which direction BlackBerry is headed, as it will include a full quarter's worth of Z10 sales. The Q10 is also about to launch, which may tap into the niche segment of hardware keyboard enthusiasts.

Can Microsoft cement itself as the No. 3 contender, or will BlackBerry retake the bronze?

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