Former Hearts winger Andrew Driver and one-time Derby and West Brom wideman Giles Barnes scored as Houston won 2-0 against the Potters at BBVA Compass Stadium.
Driver opened the scoring from a free-kick in the 11th minute and Barnes slotted the second goal two minutes from the end.
Norwich suffered a 1-0 defeat to the Timbers in the final match of their US tour.
Colombian striker Jose Valencia netted the only goal in the 53rd minute, converting a pass from Kalif Alhassan.
Ryan Bennett gave the ball away unnecessarily 40 yards out from goal and Alhassan was able to run towards goal before slipping in Valencia to fire home.