El Hamdaoui opened the scoring after 35 minutes after the Roda defence failed to clear Luis Suarez's free-kick.
Suarez, last season's Dutch League top scorer, missed the first two matches through suspension but got his first goal of the campaign early in the second half.
El Hamdaoui set up Suarez before settling the match himself with his fourth goal of the season 18 minutes from time.
NEC Nijmegen and Excelsior Rotterdam are third and fourth respectively with six points after promoted Excelsior got their second win of the season by beating Nijmegen 4-2 on Friday.
Champions Twente Enschede, whose first two matches were goalless, ended a scoring drought of 237 minutes when Marc Janko scored on the counter-attack at Vitesse Arnhem after 58 minutes.
Costa Rican Bryan Ruiz set up Luuk de Jong eight minutes later to double the lead and repeated the feat for the third goal in added time to put Twente fifth with five points.
Elsewhere, Groningen and Heerenveen secured home wins over Graafschap Doetinchem and NAC Breda respectively.
