The hosts started in determined mood following Inter's 2-2 draw at Bari on Saturday and Ronaldinho took an Alessandro Nesta cross on his chest on three minutes before sending a spectacular overhead bicyclekick just off target.
Arca fed Downing on the left and his shot looped up off James Milner into the heart of the area, where Tuncay produced a stunning bicyclekick that flew past Friedel's left hand and nestled in the bottom corner.
Clint Dempsey put the U.S. ahead in the 36th minute but the Americans, using a new-look defense that featured Omar Gonzalez and Timmy Chandler, gave up the lead when Juan Carlos Garcia tied the score with a bicyclekick in the 40th at San Pedro Sula.