Sundowns made three changes to the side that beat Al Ahly, as goalkeeper Reyaad Pieterse got his first start in the competition alongside recalls for Teboho Mokoena and Lesedi Kapinga while Al Hilal had former Cape Town City midfielder Abdul Ajagun in the line-up.
The Brazilians had a perfect start after Peter Shalulile gave them the lead within the first two minutes with left-footed strike that found the bottom corner at the near post after a diagonal pass by Themba Zwane in the box.
However, the Tshwane giants were reduced to ten men in the 11th minute after Brian Onyango shoved down Eid Mugadam, who was going clear on goal on the edge of the box and after surviving the free-kick unscathed, the visitors sacrificed attacker Zwane and brought on Grant Kekana to plug the gap at centre-back.
The Blue Wave were threatening to get back into the game but Sundowns doubled their lead on the half-hour mark thanks to a sensational long range free-kick by Mokoena that dipped under the crossbar and into the back of the net.
Al Hilal were finding spaces in and around the Brazilians' box in the early stages of the second stanza, which resulted in Yasir Mozamil pulling a goal back with low strike in the box after he was left unmarked.
However, Morena restored a two-goal lead for the visitors on the hour-mark with a stunning volley to the far corner after a through ball by Kapinga from a quick counter-attack.
With the visitors comfortably, the coaches made a double change in the 73rd minute, as Andile Jali and Shalulile made way for Bradley Ralani and Sibusiso Vilakazi.
Morena added another goal for the visitors and completed his brace in the last minute with a neat finish into the bottom corner from a swift break attack.
Al Hilal were awarded a penalty in stoppage time for a foul in the box and while Pieterse saved Mohamed Abdelrahman's spot-kick, Osman Mokhtar pounced on the rebound with the final kick of the game.
Sundowns: Pieterse, Lakay, B.Onyango, De Reuck, Morena, Jali, Mokoena, Domingo, Kapinga, Zwane, Shalulile.
Subs: Mweene, Kutumela, Kekana, Modiba, Maema, Ralani, Erasmus, Maboe, Vilakazi