Zamora led 1-0 at the break but Boca produced a five-goal second half as Luis Vargas was sent off, to make it four wins from as many matches in Group Five.
Boca - six-time Copa Libertadores champions - are six points clear of second-placed Wanderers, who travel to Palestino on Thursday.
Lowly Zamora - without a point in the group - made a dream start to proceedings, albeit controversially, at Estadio Rafael Agustin Tovar in Barinas, after Venezuelan teenager Jhon Murillo was on hand to fumble a rebound over the line.
Replays suggested Murillo, 19, handed the ball before it crossed the line.
The Argentine visitors eventually hit back six minutes into the second half, with Martinez springing the offside trap and chipping the ball over Zamora goalkeeper Alvaro Forero.
Zamora midfielder Vargas was sent off in the 56th minute for a second bookable offence and Colazo found the back of the net via a low free-kick moments later.
Boca put Zamora to the sword from that moment onwards, with Colazo adding a third in the 71st minute before Andres Chavez scored a goal of his own six minutes later.
Martinez completed the scoring in the second minute of stoppage time with a sensational scissor-kick.
Paolo Guerrero and Felipe were both on target in the second half as Corinthians accounted for Danubio 2-1 in Montevideo.
After a scoreless opening half and Renato Augusto's skied penalty just past the hour-mark, Peruvian forward Guerrero broke the deadlock with a powerful volley in the 70th minute.
Felipe doubled the Brazilian side's lead 10 minutes later after glancing a header past Franco Torgnascioli, before substitute Gonzalo Barreto pulled a goal back in the third minute of stoppage time.
Corinthians top Group Two with three successive wins, six points clear of Sao Paulo and San Lorenzo.
In other results, The Strongest rallied to beat Universidad de Chile 5-3 in a Group Four thriller.
Tigres UANL remain unbeaten after three Group Six games after routing San Jose 4-0, while Group Eight pacesetters Racing Club accounted for Sporting Cristal 2-0.
