Donovan, who led Major League Soccer with 20 goals last year, broke the shutout with a penalty kick in the 80th minute after United's Rodney Wallace committed a handball in the penalty area to give the Galaxy the penalty kick.
Donovan tied the score in the 86th minute by beating three defenders and heading Kyle Patterson's left-wing crossing pass from six yards.
Gomez made a penalty kick in the 44th minute after being fouled in the penalty area by the Galaxy's Dema Kovalenko. Pontius, a rookie from UC Santa Barbara, scored his first goal in the 62nd minute on a curving 18-yard shot.
D.C. United's Ben Olsen played his first game since June 29. Olsen, who was replaced in the 72nd minute, missed all but one game last season because of slow recovery from ankle surgery.
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