Tshepang Moremi scored the decisive goal in the second half after Yanela Mbuthuma had opened the scoring for the Buccaneers, with Pule Mmodi briefly restoring parity for Amakhosi.
The encounter began with both teams showing plenty of intensity, but Chiefs created the first clear opportunities. Wandile Duba was denied by Pirates goalkeeper Sipho Chaine in the 13th minute after being played through by Mduduzi Shabalala.
Mbuthuma eventually broke the deadlock in the 24th minute. The Pirates forward found space behind the Chiefs defence and fired towards goal, with his effort taking a deflection off Thabo Moloisane before beating goalkeeper Brandon Petersen.
Chiefs responded positively and drew level in the 30th minute through Mmodi, who capitalised on a costly handling error by Chaine to tap the loose ball into an unguarded net.
Both sides continued to search for another goal before the interval, but the teams went into half-time with the score at 1-1.
Moremi delivers the decisive blow
Pirates returned from the break with renewed attacking intent and regained the lead in the 55th minute.
Thapelo Mokobodi produced an excellent forward run before releasing Moremi behind the Chiefs defence. The winger made no mistake, calmly finishing past Petersen to put the Buccaneers 2-1 ahead.
Moremi nearly extended the advantage when his effort struck the woodwork, while another opportunity went begging as Pirates looked to put the contest beyond their opponents.
Chiefs pushed for another equaliser but struggled to find a breakthrough against a determined Pirates defence.
Their hopes of rescuing a point suffered another setback in stoppage time when defender Inacio Miguel was sent off after receiving a second yellow card.
Pirates held on to secure a memorable derby victory and their sixth win in the last seven Soweto Derby meetings.
Pirates reclaim top spot as Chiefs suffer setback
The victory extended Pirates' winning run in the Betway Premiership to seven consecutive matches and took them to the top of the standings at the time, with 25 points from nine matches.
The Buccaneers also maintained their perfect home record in the league this season.
For Kaizer Chiefs, the defeat marked their first loss of the 2026/27 league campaign and extended their winless run in the competition to four matches.
The result gives Pirates an important psychological boost in the rivalry, while Chiefs will need to respond quickly as the season continues.
Soweto Derby goals
• Orlando Pirates: Yanela Mbuthuma 24', Tshepang Moremi 55'
• Kaizer Chiefs: Pule Mmodi 30'
Final score: Orlando Pirates 2-1 Kaizer Chiefs