Lobi started like a house on fire, going on the attack from the word go. While Sundowns set back, the options were gradually opening on their end as the first period progressed.
A sterling reaction save from Olufemi Kayode denied Ricardo Nascimento from opening the deadlock through a point-blank header from a corner kick by Gaston Sirino on eight minutes, while Anthony Laffor squandered another opening 10 minutes later.
The Nigerians were made to pay for their indecisive finishing through Laffor running on the end of a cross-field ball from Sirino to tap into an empty net close to halftime.
Stars were handed a way back through a penalty, which Yaya Kone converted by sending Kennedy Mweene the wrong way with the last kick of the half.
After two stunning saves denied Mbah and Sunday Adentunji, Mweene could do nothing to stop Austin Ogunye firing past him from close range after 52 minutes.
With Sundowns struggling to carve out chances, Pitso Mosimane introduced fresh legs as Phakamani Mahlambi came on for Coetzee towards the final quarter.
However, Sundowns began tiring as the game draw to a conclusion, with the Nigerians allowed too much time and space on the ball in attack and defence.
As a result, Lobi ended off as victors to get their maiden group stage campaign off to a positive start in Enugu.
Sundowns: Mweene, Coetzee, Lebusa, Nascimento, Kekana, Mabunda, Morena, Lakay, Sirino, Laffor, Maboe.
Subs: Pieterse, Langerman, Madisha, Ngcongca, Manyisa, Mahlambi, Arendse.