In the end, Vincent Pule’s 67th minute goal proved the difference as United were unable to turn a number of promising positions into more clearcut scoring opportunities.
With so much on the line for both teams and a packed out Harry Gwala Stadium bursting at the seams, the scene was well set for a thriller.
Home keeper Richard Ofori had some early work to do as he kept out a 25-yard effort from Thembinkosi Lorch, before there was a close escape for Maritzburg defender Rushine de Reuck when he brought down Innocent Maela right on the edge of the penalty box, with a free kick rather than a spot kick the outcome.
An under-hit back pass from Brian Onyango in the 14th minute nearly let in Lorch to score, but veteran defender Nazeer Allie showed all of his experience when he got back to clear off the line.
Maritzburg began to find more rhythm to their play around the 20 minute mark and Allie was involved at the other end of the park when he ran onto a Mxolisi Kunene free kick, but with the goal at his mercy, he arrived a fraction too late to get a touch to the ball.
More followed from the KZN side as debutant Bongokuhle Hlongwane sent a header at Bucs keeper Wayne Sandilands before going close with a shot from a tough angle in the 27th minute after having been set free by Siphesihle Ndlovu.
It was the Soweto side though who were to end the first half on top and they came close with a couple of opportunities as Pule was inches away from scoring from the acutest of angles before Lorch dragged a shot wide from a very good position on the edge of the box.
The pattern of play continued after the interval; Pirates slightly on top, but Maritzburg always looking dangerous when they did manage to attack - and within the opening 10 minutes of the second half the Sea Robbers had chances as Lorch shot straight at Ofori before Justin Shonga scuffed a shot wide.
The visitors had been asking more of the questions and one of those went unanswered in the 67th minute when some superb combination play between Lorch and Luvuyo Memela resulted in the ball deflecting off Onyango, onto Pule’s foot, and into the net.
Onyango looked to try and make amends a minute later when he got on the end of a cross in the opposition box, but Sandilands was well positioned to make a good save.
With home keeper Ofori effectively playing as a defensive sweeper, the Team of Choice threw bodies forward in the closing 20 minutes as they gave everything to try and at least salvage a point.
But despite their efforts, Sandilands remained largely untested as Pirates defended resolutely to go three points clear at the top of the table.
Maritzburg: Ofori, Kunene, Allie,De Reuck Onyango, Makaringe, Timm, Hlongwane, Mokate, Ndlovu, Shandu.
Subs: Mpandle, Xulu, Matsi, Kutumela, Farmer, Mekoa, Moseamedi.
Pirates: Sandilands, Jele, Munetsi, Maela, Dube, Motshwari, Nyatama, Pule, Memela, Shonga, Lorch.
Subs: Mpontshane, Mabaso, Gabuza, Ndengane, Mulenga, Qalinge, Makola.