Boca are leading Group A with 29 points, three points clear of second-placed Argentinos Juniors, with three rounds of the regular phase remaining.

The top eight teams from each of the two groups progress to the round of 16.

The hosts thought they had struck early when Lucas Menossi tapped home after seven minutes, only to see the goal disallowed for an offside in the build-up.

Boca eventually found the breakthrough in the 38th minute, when Rojo capitalised on a poor defensive clearance following a corner to score with a scuffed shot.

Rojo emerged as Boca’s hero once again early in the second half, heading Nicolas Fernandez’s goal-bound shot off the line, but the visitors’ defence was undone in the 61st minute when Menossi headed in from close range to draw Belgrano level.

Zenon, however, restored the lead for Boca in the following minute with a fine finish from an Edison Cavani assist, and Palacios sealed the rout, firing into an open goal 14 minutes from time.

Belgrano sit 12th with 14 points.