Marino struck within a minute after being sent on in place of Nicolas Gaitan, who had stood in for the suspended Juan Roman Riquelme, by coach Alfio Basile.
The midfielder headed home a corner in the 46th minute and added his second in the 51st with a shot from 30 metres that went in at the base of the near post.
Argentinos had stunned Boca's packed Bombonera stadium in the first half with headed goals from forwards Gabriel Hauche and Nicolas Gianni as the Apertura championship began a week late.
The delay was caused by the massive debts of Argentine clubs, resolved by a government injection of money into the impoverished game and takeover of television broadcasting of matches.
River Plate, Boca's arch-rivals, fared worse, going down 2-0 at Banfield with a line-up that appears over-reliant on old hands Ariel Ortega and Marcelo Gallardo, both well into their thirties.
The goals were scored by Uruguayans Santiago Silva, with a shot from outside the box in the opening minute, and Sebastian Fernandez, who chested the ball down and volleyed home from close to the penalty spot after half an hour.
Title holders Velez Sarsfield scored seven minutes from time through substitute forward Jonathan Cristaldo, an Argentina youth international, for a 1-0 win over Colon in Santa Fe.
CAPPA ANGRY
Huracan, pipped at the post to the Clausura title by Velez in July, have lost several first-choice players in the transfer market and made a losing start, going down 2-1 to Lanus.
Paraguayan Santiago Salcedo, signed from Newell's Old Boys during the off-season, scored both goals for Lanus, who did not miss striker Jose Sand, last season's leading scorer who has moved to Al Ain in Abu Dhabi for $10 million.
Angry Huracan coach Angel Cappa, whose side were admired for their style of play in the Clausura, criticised the disorganisation of the club whose new signings have yet to be registered.
"A team is the product of training sessions, not improvisation," Cappa was quoted as saying.
"We practised on Friday afternoon with the team that was going to play (on Sunday) and that night three players had to drop out because the transfers hadn't been completed so we had to improvise on the spot."
South American champions Estudiantes, who lifted their fourth Libertadores Cup in July, won 2-0 at Arsenal. Mauro Boselli and defender Cristian Cellay scored the goals, both with headers.
