Themba Zwane, Percy Tau (two), Ricardo Nascimento and Thapelo (two) Morena all scored for The Brazilians and Pirates had no response.
Pirates could have taken the lead as early as the second minute, when Tendai Ndoro played a sumptuous ball through for Gift Motupa, who did well to round Denis Onyango but could only direct his shot onto the far-side upright.
Downs then had a good opportunity at the opposite end as Tau broke away to set Zwane up outside the area, but the latter skied his shot wide of the mark.
Zwane grabbed the lead for the defending champions as he finished at the second attempt, after the ball got stuck under his feet from Khama Billiat's well-placed cross from inside the box.
Tau then doubled the lead in the 43rd minute to end off a brilliantly worked team goal, which saw Zwane find Billiat, who neatly flicked it on for the striker to slot home.
Nascimento scored his first Absa Premiership goal from the penalty spot in the 63rd minute, after James Okwuosa's nightmare debut continued with a foul on Tau in his own area.
Morena could have added a fourth when he broke through the Bucs defence and rounded Jackson Mabokgwane, but the fullback's shot came off the near-post.
Morena then made up for his earlier miss as he tapped home in the 69th minute, after Tiyani Mabunda's pass beat Mabokgwane and Okwuosa.
The former Bloemfontein Celtic winger then completed his brace just seven minutes later, as Tau beat the offside trap to set him up for a simple finish into an empty net.
The visiting supporters then began to disrupt proceedings as they vandalised SuperSport TV's cables.
Tau then completed his brace as the Buccaneers conceded six for a second time this season, with the club's supporters then raiding the pitch to bring the match to a complete stop.
Play eventually resumed more than an hour later, with the remaining eight minutes allowing Mpho Makola and Ndoro opportunities to make the score more respectable but both failed to find the back of the net.