The Paraguayan youngster led the category on his previous two outings in Italy and Kenya but was forced to retire on both occasions with technical troubles.
It was third time lucky for Dominguez in Greece who, after seizing the lead from a struggling William Creighton on Saturday, was never-headed.
"It is a feeling I have never had," gushed Dominguez following the win. "It's always been a dream of mine to win a WRC event and just to be here is amazing, especially at an event like Greece."
A mature drive through the final three rugged speed tests confirmed his triumph in the all-Ford Fiesta Rally3 category and he headed Creighton by 49.6sec at close of play. Epaminondas Karanikolas rounded out the podium 44.4sec further back on his Fiesta debut.
Panos Ismailos completed the leaderboard at the end of a drama-filled weekend. He was over 20 minutes back, with the majority of that time being lost on Friday afternoon when his car’s fire extinguisher was unintentionally activated by a flailing windscreen wiper.
Finland
Italy
Hungary