A first-half goal by Etoile captain Ammar Jemal was enough to give the Tunisian side a 2-1 aggregate win over the Buccaneers in Sousse.
Pirates got proceedings underway and showed clear intent of attack as they launched forward to try and find a crucial away goal.
The best chance of the half for the Buccaneers came in the 18th minute when Thabo Rakhale sent a tame effort across goal from an acute angle, from Thamsanqa Gabuza's through ball.
The hosts were dealt a blow when star striker Baghdad Bounedjah was forced off with an injury, and replaced by Brazilian Diogo Acosta in the 20th minute.
Three minutes later, Etoile made the most of their opportunity at the other end when Jemal tapped in after Felipe Ovono fumbled a deflected cross from the left flank.
In the 37th minute, substitute Acosta had a good opportunity to double the home side's lead, but his headed effort went narrowly over Ovono's bar.
Bucs looked to pull one back before half-time when Gabuza tried to release Erasmus on a run, but the striker was caught off-side two minutes before the break.
Pirates looked more offensive in the seciond half as they won a corner within two minutes, which Happy Jele headed straight towards Aymen Mathlouthi.
Etoile had a rare opportunity to attack in the 54th minute when they broke on a three-on-one counter attack, but Thabo Matlaba was on hand to rescue the Bucs defence.
Three minutes later Erasmus rose highest to latch onto a Rakhale cross, which caused some confusion between Mathlouthi and Jemal, but the skipper cleared his lines at the second attempt.
Just a minute later, Rakhale failed to control a lobbed pass inside the Etoile box, and Mathlouthi did well to steal it right from under the midfielder's feet.
A double change in the 71st minute saw Mpho Makola and Rakhale withdrawn for the fresh legs of Sifiso Myeni and Menzi Masuku.
Despite the substitutions aiding in Pirates' offensive play, Etoile's disciplined defense ultimately proved too strong for the Bucs, who succumbed to their second continental final defeat in three years.
Orlando Pirates XI: Ovono; Matlaba, Gcaba, Sangweni, Jele; Masalesa, Motupa, Makola (Masuku 71'), Rakhale (Myeni 71'); Erasmus, Gabuza.
Pirates subs: Mhlongo, Nyauza, Sarr, Mahamutsa, Myeni, Masuku, Majoro.
Etoile du Sahel XI: Mathlouthi, Mathlouthi, Nagguez, Jemal, Boughattas, Tej (Sadaa 84'), Trabelsi, Kom, Lahmar, Brigui, Msakni, Bounedjah (Acosta 20').