Fabian Johnson and Clint Dempsey were both on target as the hosts continued their preparations for Brazil with a hard fought success in New Jersey
Jurgen Klinsmann's men overcame a stern test from a dangerous Turkish side, building on Wednesday's 2-0 success over Azerbaijan with another impressive win.
Turkey wasted a number of openings in an entertaining game at the Red Bull Arena in Harrison, New Jersey, and their failings in front of goal proved pivotal as the hosts held on despite a late rally from Fatih Terim's charges.
The US will now face Nigeria on Saturday in Jacksonville before opening their World Cup campaign against Ghana on June 16.
In the opening exchanges, it was Turkey who created the first chance after 11 minutes as they almost capitalised on some sloppy United States defending, Nuri Sahin curling an effort off the outside of the post from just inside the area.
Jozy Altidore netted four minutes later, only for the strike to be disallowed for a foul in the box.
Turkey continued to have the better of the early play and should have taken the lead when midfielder Inan fired high and wide when he really should have been hitting the target.
And the visitors were made to pay for their profligacy in the 26th minute as Klinsmann's side opened the scoring.
Johnson surged at the heart of the Turkey defence before laying the ball off for Michael Bradley, who then lofted an exquisite pass into the path of the Hoffenheim man who scored with a confident low finish.
Chances dried up in the latter part of the first half, but the United States were gifted a second goal shortly after the interval.
Turkey defender Hakan Balta failed to deal with a low cross into the box from Brad Davis, presenting attacking midfielder Dempsey with the simple task of tapping in from point-blank range.
Terim's side were consistently wasteful in front of goal as they spurned a number of opportunities to get back into the game.
Gokhan Gonul was denied by a fine save at the near post from USA reserve goalkeeper Brad Guzan, before Mustafa Pektemek lashed another effort wide. Turkey did finally find a way through, Selcuk Inan converting from the spot late on after Geoff Cameron had handled Pektemek's strike on the line.
However, Turkey could not complete a comeback in injury time, leaving Klinsmann and his squad to enjoy a morale-boosting victory.