Tefu Mashamaite scored the game's decisive goal in the 28th minute, glancing a header past Senzo Meyiwa from George Maluleka's inswinging set-piece from the left.
Mashamaite was left unmarked on the penalty spot and was quick to accept Pirates' invitation to score after Daine Klate failed to move up with his defensive line and played the Chiefs man onside.
Chiefs were good value for their lead having bossed much of the first half, Mandla Masango forcing the first save of the game from Meyiwa when he met Tsepo Masilela's left-wing cross on the volley after 10 minutes.
Pirates had a golden opportunity to score when Oupa Manyisa and Kermit Erasmus combined beautifully in the 22nd minute. Manyisa fed it through to the striker, who cut it back to the midfielder on the penalty spot, but his first-time shot was saved by a diving Khuzwayo.
It was Pirates' only sniff of goal in the first 45 minutes as Chiefs stroked the ball around confidently, but the game was still on a knife-edge as Pirates were enjoying 55 percent of the possession.
Vladmir Vermezovic's side came out for the second half more determined to get that goal and showed their intent when Erasmus stung the palms of Khuzwayo in the 52nd minute after Pirates' best move of the game.
The second half continued in end-to-end fashion as both sides tried to get forward at every opportunity, Chiefs relying more on transitions and counter-attacks the longer than game went on.
Stuart Baxter brought on Bernard Parker and Siphiwe Tshabalala to add experience as his side showed organisation and discipline to thwart every Buccaneers attack.
Pirates substitute Lehlohonolo Majoro forced Man of the Match Khuzwayo into an important save 13 minutes from time when he brought the ball down on his chest and fired it towards the near post.
Parker had a chance to put some gloss on the scoreline but Meyiwa stood firm to block his close-range shot after he cut inside his marker.
But Khuzwayo earned his clean sheet in the 88th minute as Erasmus fired off a powerful effort from outside the box, but the Chiefs stand-in dived smartly to his left to keep it out.
Chiefs held on to win their 15th top eight title, their second as the MTN8, and made it 10 straight competitive wins this season.
