The win means Gallants have won both matches at the start of the league season while for Pirates it is two consecutive losses and thet are yet to open their account.
The Buccaneers started the contest well with Boitumelo Radiopane testing home goalkeeper Washington Arubi in the very first minute.
Pirates continued with their early momentum and took the lead after 16 minutes when a low cross from Deon Hotto was swept into the back of the net by Patrick Maswanganyi.
Arubi was then called upon again soon after as the shot-stopper produced a magnificent triple save, diving full stretch to deny Oswin Appollis and then a double follow-up.
Gallants then equalised on the stroke of the halftime break when a good team move was brilliantly finished off with a close-range volley from Daniel Msendami.
Pirates dominated possession after the interval looking for their second strike but were well kept out by solid defending from the hosts, who were content to play on the counter-attack.
Gallants patiently waited for their opportunity and, in the dying stages from their own half, scripted a play that saw substitute Jaisen Clifford arrive at the far-post to finish and take all three points.
It was tough blow for new Orlando Pirates head coach Abdeslam Ouaddou as he went down to his former club, especially after an opening day defeat against Sekhukhune United.
Gallants' new mentor Alexandre Lafitte will be basking in a glorious start as he reflects on taking six points from six to start his rein in South Africa's top-flight.