RABAT, Morocco -- A thumping finish from Adil Boulbina late in extra time sent Algeria through to the Africa Cup of Nations quarterfinal at the Democratic Republic of Congo's expense, following a tense 1-0 victory at the Moulay El Hassan Stadium in Rabat on Tuesday.
The 2019 champions will now meet Nigeria, who dispatched Mozambique 4-0 in Fes on Monday, in Saturday's quarterfinal in Marrakesh.
Substitute Boulbina, an extra-time replacement for Farès Chaïbi, picked up Ramiz Zerrouki's through ball in a left channel and advanced towards the Congo goal before slamming a powerful right-footed effort beyond Lionel M'pasi from outside the area in the 119th minute.
The victory was Algeria's first in a knockout game at the Nations Cup since they defeated Senegal to win the title in Cairo in 2019.
Algeria had monopolised the ball during much of a tenacious first half, but struggled to convert the pressure they imposed on the Congo backline into clear chances, with Samy Moutoussamy adding an extra, energetic screening layer in front of the Leopards defence.
Mahrez not looking as sharp as he has done earlier in the tournament, failed to control a through ball during the opening minutes, before clumsily firing a set piece straight at Aïssa Mandi's midriff after Rafik Benghali had launched himself at Joris Kayembe in search of a freekick.
Algeria had earlier had calls for a penalty waved away after Samuel Moutoussamy trod on Mohammed Amoura in the box, dislodging his boot in the process, although a series of Algeria fouls across the pitch appeared to go unpunished by Egyptian referee Mohamed Mansour, prompting the ire of the Congolese bench.
Fares Chaibi had his freekick cleared after another refereeing decision went the way of the Leopards, while the Congolese had to smuggle the ball away on 20 minutes after Benghali's cross caused consternation in the DRC box following a sharp interchange with Mahrez.
While Algeria constantly probed the Leopards backline, finding dangerous pockets consistently as they advanced towards goal, Congo had a threat of their own in the form of the rangy Cédric Bakambu, a handful as he sought to go it alone against Mandi and Ramy Bensebaini.
In the early minutes he'd delivered a statement of intent by bundling the latter over as the Leopards sought to play direct, and grew increasingly dangerous as the half wore on.
On the break, he had a cross-goal shot saved by Luca Zidane, when passing to the advancing Elia Meschak might have been the better option, before meeting Aaron Wan-Bissaka's cross to send an angled header wide of Zidane's post just after the half-hour mark, having again got the better of Bensebaini.
Amoura served notice of his brooding threat after racing towards goal only to fire wide late in the half, while Axel Tuanzebe should have done better when -- unopposed -- he sent a header from a corner beyond Zidane's right-hand post.
Algeria appeared more tentative after the break, with an injury to midfield general Ismaël Bennacer -- replaced in the 49th -- denying them the control that they'd enjoyed during the opening period.
DRC started to enjoy themselves more, with Hicham Boudaoui denying Chancel Mbemba at the backpost with a brave block from a Leopards corner, although Mahrez did send a 67th-minute freekick narrowly over, prompting complaints from Bensebaini about the skipper's desire to go for goal.
It was to be Mahrez's last significant act, as he was withdrawn 21 minutes from time as both head coaches shuffled their pack to attempt to seal victory over the final stages.
Edo Kayembe, who entered the fray alongside Gaël Kakuta, shot straight at Zidane after being picked out on the edge of the box two minutes after his arrival, while another sub, Algeria's Anis Hadj Moussa, sent a tame effort straight at Mpasi as both sides looked to force the issue.
The Algeria fans got off their seat for the lively Amoura -- top scorer across Africa during World Cup qualifying -- as he tore down the right flank in the 77th minute, opting to shoot at Mpasi rather than cross, with both Hadj Moussa and Ibrahim Maza joining him in the attack.
Algeria turned to Baghdad Bounedjah, match-winner in the 2019 AFCON final, in the 83rd minute as Vladimir Petkovic looked to avoid extra time, but it was Hadj Moussa who had Algeria's best chance of the final minutes, firing straight at Mpasi again as the Leopards failed to deal with a Fennecs corner.
At the death, substitute Zineddine Belaïd made a crucial intervention to direct Michel-Ange Balikwisha's fine cross out of play with Fiston Mayele lurking in wait to ensure the pair would play another half hour.
Clear chances were limited during extra time, although Bensebaini did meet a Hadj Moussa freekick to send a header straight at Mpasi in the 106th, while Chaibi's lunging finish prompted a short save from the Congo keeper down to his right during the opening stages of the second period.
The loss of Moutoussamy through injury in the 109th appeared to revitalise Algeria's flagging forwards, and it was Al-Duhail's Boulbina, entering the fray only six minutes earlier, who capitalised, finding space on the run outside the Congo box before slamming home his first goal of the tournament.
