Rodney Ramagalela opened the scoring for Leopards but Pirates came back, with Tlou Segolela equalising, a brace from Ndumiso Mabena and the clincher from Oupa Manyisa.
Leopards got off to a flying start, when Ramagalela sent the ball into the roof of the net from outside the box inside four minutes.
But just four minutes later Bucs were back on level terms, when Manyisa played a superb diagonal pass into the box for Segolela to nudge past the onrushing Azwindini Maphaha.
The hosts took the lead in the 19th minute, when Mabena finished with a first time shot at the near post, off a low cross from Mpho Makola.
Maphaha pulled off two great saves to keep scores level, tipping Khetowakhe Masuku’s effort over the crossbar in the 22nd minute, and denying him again six minutes later.
Ramagalela used his strength to get past Ayanda Gcaba in the 31st minute before firing a low shot, but Brighton Mhlongo, who had a great game on debut, dived to his right to keep the ball out.
The Buccaneers increased their lead two minutes later from a free-kick. Manyisa releasing Makola on the left, who crossed the ball for Mabena to finish from the centre of the penalty area.
Lidoda Duvha almost replied just before half-time but Mongezi Bobe was denied by another good save from Mhlongo before Ramagalela blazed the rebound over the crossbar.
The second half was more of the same with the Buccaneers doing most of the attacking.
Rooi Mahamutsa should have added a fourth goal on the hour mark, but after meeting a cross from Masuku he sent his header wide from close range.
Bucs wrapped the game up 20 minutes from time, when Manyisa collected a neat backheel from Mabena before placing the ball past Maphaha from just inside the box to seal a comfortable win.
With one game to play, Leopards stay bottom of the log on 23 points, with Chippa just above them on 25. Ajax Cape Town are third from bottom, on 28 points, and could still be in trouble if they lose their final match and the Chilli Boys win. Lidoda Duvha, however, cannot avoid either last place (automatic relegation) or second last (promotion/relegation play-offs).