The United Kingdom’s antitrust regulator on Friday approved Microsoft’s $69 billion acquisition of Santa Monica, California-based video-game maker Activision Blizzard, setting the stage for the deal’s completion after 21 months of regulatory wrangling around the globe.

The pending completion of the deal serves as a monumental achievement for Microsoft president and vice chair Brad Smith, a former chief legal officer of the Redmond, Washington-based company who shepherded the deal through a maze of obstacles, an effort that at times seemed doomed to failure.