Defender Fabian Johnson combined with Michael Bradley to score a well-executed goal in the first half before Clint Dempsey added a second after the break. Turkey, who failed to qualify for the World Cup, got a consolation goal in the last minute of normal time when Selcuk Inan converted a penalty after Geoff Cameron had been ruled to have handled the ball in the box.
Turkey were unlucky not to score earlier when captain Nuri Sahin hit the post and, in front of a full house at Red Bull Arena in New Jersey, the US had some anxious moments in defence, but they held firm and looked sharp in attack. For the opener, Bradley deftly flicked the ball over the Turkish defence into the path of Johnson, who hit a perfect left-footed volley into the net for his first international goal.
Dempsey gave the Americans a 2-0 lead in the 52nd minute with a typical poacher's goal, poking the ball in after Kivrak fumbled Timmy Chandler's cross from the left.
Turkey got on the scoreboard in the dying moments after a mix-up in the American defence. Cameron lost the ball to Mustafa Pektemek then failed to get his arm out of the way when the Turkish substitute shot.
In Moenchengladbach, Germany came from a goal behind to draw 2-2 with a hard-working Cameroon side. The Germans looked some way off top form without several key players including captain Philipp Lahm and first-choice goalkeeper Manuel Neuer. Joachim Loew's side almost got off to a perfect start when Mesut Oezil, unmarked in front of goal, somehow managed to shoot wide.
Cameroon struck in the 62nd minute when Samuel Eto'o's shot was saved by Roman Weidenfeller but the forward was in the right place to tap in a subsequent cross.
Their joy was short-lived, however, with Thomas Mueller charging into the box to head in a Jerome Boateng cross four minutes later and Andre Schuerrle tapping in after a surging run by substitute Lukas Podolski. But Cameroon refused to lie down and Eric-Maxim Choupo-Moting picked up the ball outside the box and drilled an unstoppable left-foot shot past Weidenfeller in the 78th minute.
A brilliant solo effort from Eden Hazard after Romelu Lukaku's opener were enough to give Belgium a comfortable 2-0 win over Sweden in Stockholm.
Belgian dominated for much of the game, with Kevin De Bruyne hitting the post after 15 minutes, and Sweden lacked cutting edge in the absence of Zlatan Ibrahimovic, missing with a back injury.
France almost eased Didier Deschamps' concerns over their readiness for the finals with a win over Paraguay. Antoine Griezmann fired them ahead with eight minutes to go in Nice, only for Victor Caceres to equalise with a last-minute header.