Masandawana welcomed back Gaston Sirino, whereas Bucs recalled Thulani Hlatshwayo and Thabang Monare aftter their triumph over Al-Ahli Benghazi in the CAF Confederation Cup on Sunday.
Sundowns broke the deadlock on 12 minutes when Peter Shalulile timeously beat the offside trap to bring down a ball from Rivaldo Coetzee before going on to find the bottom-corner.
The Buccaneers were afforded no time on the ball by the Brazilians before the midway point, although they had a decent opening in the area from Gabadinho Mhango fluffed.
Pirates rallied repeatedly despite trailing and within three minutes of the half-hour mark drew level from a simple finish at the far post from Mabasa following a delivery from Mhango.
Masandawana were under pressure following the final stages to halftime, as Mhango rattled the woodwork after pouncing on a loose ball in the box.
Sundowns restored parity in the first five minutes of the second stanza after Themba Zwane charged in the area from combination play outside the box to evade Sandilands for a simple finish.
The Buccaneers looked for an immediate leveller, but a half-volley from Mabasa couldn't beat Denis Onyango whilst Lebohang Maboe fizzled across the face of goal at the other end.
Sundowns could've made it three through the head of Rushine De Reuck in the last 20 minutes, but Ben Motshwari cleared off the line, before Onyango prevented an own-goal from Mosa Lebusa.
Masandawana opted to introduce fresh faces inside 77 minutes in Hlompho Kekana for Maboe and Lesedi Kapinga for Sirino.
Kapinga made an instant impact in less than a minute when he executed a belter of strike well beyond the reach of Sandilands.
The Brazilians weren't done as Kekana unleashed a thumping strike from range four minutes from time that left Sandilands in no man's land to wrap up the win and set up a semi-final meeting with Tshakhuma Tsha Madzivhandila on Sunday.
Sundowns: Onyango, De Reuck, Lebusa, Coetzee, Morena, Modiba, Maboe, Mkhulise, Sirino, Zwane, Shalulile.
Subs: Goss, Nascimento, Kapinga, Vilakazi, Mudau, Mkhuma, Kekana, Motupa, Mvala.
Pirates: Sandilands, Hlatshwayo, Jele, Nyauza, Mako, Motshwari, Makaringe, Monare, Mhango, Hotto, Mabasa
Subs: Mpontshane, Pule, Mabaso, Tshobeni, Mntambo, Dlamini, Jooste, Makgaka, Ndlovu.