Their good fortune came after third-round opponents AS Vita Club from the Democratic Republic of Congo were thrown out for fielding an ineligible player in February.
Vita Club defeated the recently crowned South African champions on away goals after a 2-2 aggregate draw in the last of the preliminary knockout rounds.
Vita had been set to enter Tuesday's draw for eight-team group phase until red-faced CAF officials belatedly discovered they had fielded an ineligible player in their first-round tie against Mafunzo from Zanzibar three months ago.
Vita Club played Idrissa Traore, a recent signing from Stade Malien, who should have been serving a three-match ban carried over the 2015 competition when he was still on the books of the club from Mali.
After being eliminated from the Champions League, Sundowns dropped into the secondary African Confederation Cup competition but were ousted from that tournament by Ghanaian side Medeama SC last week.
Vita Club were Champions League runners-up in 2014 and lifted the trophy in 1973. – Reuters
Original source: Sundowns handed Champions League lifeline