Argentine Rocha, 58, was appointed last Thursday following the resignation of Ferreira after a poor start to the season left the Greens in eighth place.
Rocha's team picked up only their fourth win of the season courtesy of Zeca's clinical 51st-minute finish following a neat exchange of passes with Spanish striker Toche and a late penalty from midfielder Vitolo.
The win lifted Panathinaikos up to sixth spot with 16 points from 11 matches and the Athens club are now seven points adrift of second-placed PAOK.
Panathinaikos, however, trail unbeaten league leaders and arch rivals Olympiacos by 15 points after Leonardo Jardim's men sealed a comfortable 2-0 home win against Kerkyra on Saturday courtesy of goals either side of half-time from Kostas Mitroglou and Dimitris Siovas.
Bottom club AEK Athens picked up a morale-boosting 4-0 away win at Veria following last weekend's derby defeat by Olympiacos.
AEK coach Ewald Lienen, who took over last month, has now guided the club to two wins in five games but they remain at the foot of the table with eight points.