Watch AFCON 2023 LIVE on beIN SPORTS | Sign up to take advantage of our 7-day free trial | AU | NZ

Dellahi punished some lax defending in the 36th minute and despite a second-half onslaught, two-time tournament winner Algeria could not find a response as it lost 1-0 to finish bottom of its group for a second consecutive AFCON, while Mauritania progressed as one of the best third-placed teams.

After two successive draws had left it in trouble, Algeria coach Djamel Belmadi dropped Riyad Mahrez to the bench as he tried to freshen up his side but it did not work as Mauritania proved a stubborn opponent.

Algeria dominated possession and Adam Ounas tried to catch out Babacar Niasse, shaping to cross and hitting a vicious inswinging shot the goalkeeper did well to claw behind.

But Mauritania stunned Algeria late in the half. Anthony Mandrea pushed away a stinging shot from Souleymane Anne, but Algeria could not clear the resulting corner and when Omare Gassama’s shot was blocked, the ball fell for Dellahi to fire in, giving Mauritania its first lead in AFCON history.

Mahrez came on at the break as Algeria tried to turn up the heat, but Mauritania remained a threat and Aboubakary Koita wriggled his way past three defenders in the box before sending a shot over when he was off balance.

At the other end, Niasse came tearing off his line to cut out Ramiz Zerrouki’s long ball forward, but needed Ibrahima Keita to scramble back and block Youcef Belaili’s shot at his unguarded goal.

Algeria was looking desperate but it was Mauritania that had the late chances to score, with Lamine Ba hitting the crossbar before Guessouma Fofana was denied by the goalkeeper.

Eleven minutes were added on and Algeria went agonisingly close again, with Baghdad Bounedjah poking the ball inches wide after Aissa Mandi’s shot was blocked by Niasse, but it was Mauritania’s night.