The 2-0 scoreline on the day, courtesy of second-half goals form Mbwana Samatta and Roger Assale, meant the side from Congo DR will hope to repeat their heroics from 2010, when they became the first African side in history to reach the Club World Cup final. They will meet either Auckland City or the Japanese national champions in the quarter-finals this December.
Mohamed Seguer's late goal a week ago ensured the game began an open one, after the hosts' coach Patrice Cateron promised his side would arrive with attacking intent with the tie still more than up for grabs. Neither team managed to convert from the early space in a lively opening, though visiting hearts were in mouths inside three minutes when Houcine Benayada was booked for a foul on the very edge of their area.
The game turned to efforts from distance, with Charles Andriamasinoro testing Mazembe keeper Robert Kidiaba with a well-struck volley following an expert chest trap, followed by Richard Boateng trying his luck for the hosts shortly after. They continued to exchange efforts from range until the best move of the half saw Alger's Mohamed Aoudia find space in the area, only to fire wide.
The second period continued to feature plenty of energy, but chances were at a premium - a state of affairs which clearly suited Cateron's side. They went close to all but sealing the title with 25 minutes to go. When a cleared corner only found Boubacar Diarra, he sent it back with interest thanks to a cute volleyed lob, only being denied by a vital header from Mokhtar Benmoussa on the line.
Benyada gave Kidiaba a scare when his bouncing shot from range flashed narrowly wide, but the crucial moment came seconds later at the other end. The fleet-footed Assale charged at the Alger backline, with his twisting and turning ending in a rash tackle from Rafik Chafai and the referee pointing for penalty. Just as in the first leg, Samatta stepped up to the spot and the result was the same, coolly firing down the middle.
Alger looked reinvigorated after going behind, with Rachid Nadji spurning a gilt-edged chance after fine work from Chafai down the wing, but they couldn't break the Mazembe resolve.
The visitors' late charge was finally ended moments later, with Zinedine Ferhat seeing red in the aftermath. A lightning-quick break from Samatta and Assale saw the former round the keeper and the latter slot home as the Congolese giants made it 60 wins from 78 to seal the title five years on from their last. Next stop, Japan.