Sundowns made only one change after they were held to a draw by Sekhukhune United, as Andile Jali was recalled while new signing Allende featured on the bench.
The Brazilians had the perfect start after Neo Maema opened the scoring in the second minute with a low strike past goalkeeper Sage Stephens.
Fawaaz Basadien had a big chance to level matters for the visitors ten minutes later after going through on goal from a counter-attack but his thumping strike was brilliantly parried over the crossbar by shot-stopper Ronwen Williams in a one-on-one.
Sundowns took control of the game after that but they were forced to make a change just before the half-hour mark after Gaston Sirino was stretchered off with a hamstring tear and he was surprisingly replaced by Thapelo Morena in a tactical switch upfront.
Steve Barker’s charges had a better resistance towards the end of the first stanza and threatened going forward as they had a penalty appeal for a header that ricocheted off the hand of Themba Zwane at the near post.
However, Masandawana eventually doubled their lead just before the halftime break courtesy of Peter Shalulile, who fired a left-footed strike across and into the bottom corner after a through ball by Morena.
Stellies played high up the pitch early in the second stanza but Rushine De Reuck came close to adding another goal for Sundowns with a header that was tipped over the crossbar by Stephens from a free-kick by Teboho Mokoena.
The Brazilians refreshed their attack with a double change on 68 minutes, with Allende getting his debut in place of Zwane while Sipho Mbule replaced Maema.
It took barely ten minutes for Allende to get his first goal for Sundowns after his well-cushioned low shot in the box went in off the bottom post after he was set up by Morena to wrap up a good win for the home side.
Here’s how they lined up:
Sundowns: Williams, Modiba, Mudau, B.Onyango, De Reuck, Mokoena, Jali, Maema, Zwane, Sirino, Shalulile
Subs: D.Onyango, Morena, Lebusa, Ralani, Mailula, Mbule, Lakay, Mvala, Allende.
Stellenbosch: Stephens, De Goede, Basadien, Andries, Van Rooyen, Mthethwa, Mendieta, Adams, Letsoenyo, Mgaga, Van Wyk
Subs: Langeveldt, Likuta, Weaver, Titus, Nduli, Sibiya, Mngomezulu, Boji, Jabaar
