The result left Sundowns second in the group on nine points, trailing leaders Al Hilal by two.
In the build-up to the encounter, the Pretoria outfit had dominated headlines following allegations that a club analyst had been suspended for allegedly sharing tactical information with opponents.
However, the controversy did little to disrupt Sundowns’ focus as they produced a composed and disciplined performance against their North African visitors.
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The Brazilians signalled their intent from the opening whistle and wasted little time asserting control. They took the lead in the sixth minute when Leon reacted quickest to a loose ball after Arthur Sales saw his effort blocked by MC Alger goalkeeper Alexis Guendouz.
Sundowns continued to apply pressure in search of a second goal, forcing the visitors onto the back foot for large spells. MC Alger’s attacking efforts were limited, with their only notable threat in the first half coming from a 25th-minute corner.
At the other end, Khuliso Mudau headed over from close range, while Teboho Mokoena rattled the crossbar as the hosts went into the break firmly in control.
MC Alger showed more urgency early in the second half, briefly testing Ronwen Williams, before tempers flared following a robust challenge on Sales by Mohamed Zougrana, leading to a heated exchange between both sides.
Sundowns eventually sealed the result in the 63rd minute when Leon met Aubrey Modiba’s delivery at the near post, guiding the ball past Guendouz to complete his brace and all but confirm progression.
As frustration mounted for the visitors, Sundowns managed the closing stages with authority, enjoying the bulk of possession and defending comfortably to see out a deserved victory.