FCD picked up two red cards in the match, one to defender Zach Loyd in the late stages of the first half. Playing down a man for half of the game was too much for the visitors to over come D.C. rode a Fabian Espindola brace and tallies from Bobby Boswell and Sean Franklin to victory.
The game would turn against Dallas as they be forced to defend their lead a man down after Loyd's rash, studs-up challenge on United midfielder Davy Arnaud earned him his second yellow of the match in the 39th minute.
United took over from there as in the late stages of the first half Espindola got his first goal on the night. The extra space from the Loyd red card allowed Eddie Johnson to send a perfect ball into the penalty box for Espindola to tap in.
The second half was all D.C. as United scored three goals within ten minutes.
Dallas would again lose their focus in second-half stoppage time, with midfielder Michel being shown a straight red card for violent conduct after taking a swat at United midfielder Chris Rolfe.
FCD must regroup as they return home next Sunday for a match with the New York Red Bulls.