Ichie Altamirano led San Sebastian with 10 points, four rebounds, four assists, and two steals in the season-opening win.
Ken Villapando got nine points, four boards, two dimes, and two steals, and Rhinwil Yambing had nine points and four rebounds.
Arellano mounted a late surge to get to within six points, 57-51, after a Joshua Abastillas putback with 1:50 left, but Felebrico was quick to answer back as San Sebastian buckled down on defense late.
The Golden Stags also punished the Chiefs for committing 24 turnovers, turning it into 30 points on their end.
Arellano fell to its first loss in two games as it saw Axel Doromal's 15-point effort flushed out.
Cade Flores added 12 points and nine rebounds in the loss.
San Sebastian 60 - Altamirano 10, Villapando 9, Yambing 9, Felebrico 7, Cosari 6, Una 6, Sumoda 4, Are 3, Shanoda 2, Escobido 2, Desoyo 2, Suico 0.
Arellano 51 - Doromal 15, Flores 12, Abastillas 8, Talampas 8, Oliva 2, Mallari 2, Tolentino 2, Sunga 2, Menina 0, Oftana 0, Mantua 0.
Quarterscores: 10-12; 27-27; 50-38; 60-51.