One of the most significant plays Sunday night at the American Airlines Center didn’t involve a player scoring a basket, it was a defensive play that prevented one. Mavericks guard Devin Harris tackled Houston center Dwight Howard to prevent an easy dunk. At the time, Dallas trailed 38-31 with just under nine minutes remaining in the first half. “It’s not even about being dirty or anything like that,” Mavs center Tyson Chandler said after Dallas’ 121-109 Game 4 victory. “It’s about holding your ground. … (That play) gets the team up because it let’s them know that guys are fired up and ready to play. Those plays the last three games have been dunks … and that just energizes them.” Harris was given a flagrant one foul for the play. Howard missed both free throws and the Mavs finished the second quarter on a 30-15 run.