The one-time U.S. national forward scored what would be the game winner as Houston held off a second half rally from Portland.
The visitors almost got an early lead, as the Timbers had three shots on goal within the opening seven minutes of the match. Once the Dynamo's midfield began to control possession, the game turned around.
Moffat, who came from the Timbers in a midseason trade, got a little bit of payback against his old club as he received the ball 38 yards away from goal and blasted a laser shot past Portland's goalkeeper Troy Perkins. The stunning strike amazed the 14,475 fans in attendence at Robertson Stadium.
Once Houston was first on the scoresheet, it continued to assert itself offensively.
Ching would beat a diving Perkins to score what would be the game's winner. The play was ignited by an excellent throw-in from Houston's set piece maestro Brad Davis that found Colin Clark who found the charging forward.
Portland responded with a better second half. The Timbers All-Star midfielder Jack Jewsbury received an headed ball from Darlington Nagbe and blasted the ball past Houston's defense to get the club back into the match at 2-1.
Still, the Timbers were unsuccessful in its attempts to equalize and Houston held on for the lead.
Follow ALEX LABIDOU on