Iliman Ndiaye's first-half tap-in was enough for Senegal to beat 10-man Mali and book their place in the semi-finals of the 2025 Africa Cup of Nations (Afcon).
The Everton forward was on hand to convert from five yards after Mali goalkeeper Djigui Diarra failed to gather Krepin Diatta's low ball from the right.
Diarra tipped a shot from El Hadji Malick Diouf on to the bar in first-half stoppage time, just before Eagles captain and Tottenham midfielder Yves Bissouma was sent off for a second bookable offence.
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Senegal keeper Edouard Mendy denied Abdoulaye Diaby in the second half in Tangier before Diarra made saves from Sadio Mane and Pathe Ciss.
Ciss spurned another chance for the 2021 champions, shooting straight at Diarra after capitalising on a defensive error, and the Eagles keeper then diverted Lassine Camara's dipping volley on to the right-hand post in added time.
Mali exit the tournament without winning a game after their repeated ill-discipline finally cost them, having had a man sent off for the third consecutive outing in Morocco.
The Eagles will be happy to see the back of referee Abongile Tom, who was also in charge of their last-16 match against Tunisia and showed Woyo Coulibaly a straight red card.
Senegal will discover their last-four opponents on Saturday when record seven-time champions Egypt face holders Ivory Coast in Agadir.
Senegal had eased past Sudan despite an early scare in their last-16 tie, while Mali had needed a late equaliser and then penalties to get past Tunisia - having gone down to 10 men in the 26th minute of that contest.
The first big talking point came in the third minute when the Eagles were denied a potential penalty after Lassine Sinayoko was caught by returning Senegal skipper Kalidou Koulibaly just inside the box.
Yet the video assistant referee did not get involved, with South African Tom not sent to his pitch-side monitor to review the incident.
Teranga Lions midfielder Pape Gueye had already sent two efforts wide before Bissouma picked up his first booking midway through the half for catching Mane with a flailing arm.
Diarra saved two penalties in the shootout against Tunisia but was at fault for Senegal's opener as Diatta's cutback squirmed under his body and Ndiaye was presented with an empty net.
Mali rarely threatened and their task got harder when Bissouma, who has not played a single minute for club side Tottenham this season, picked up his second caution for a late challenge on Idrissa Gana Gueye on halfway.
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Tom Saintfiet's Eagles rarely looked like grabbing a leveller, but Mendy got down smartly to cut out a threatening low cross from Sinayoko early in the second half and the former Chelsea man also made a low save from Diaby's effort from a free-kick.
Instead it was up to Diarra to make a string of saves to keep his side in contention, yet Mali could not muster a sustained period of pressure or carve out another chance during seven minutes of added time.
Mali exit at the quarter-final stage for the second tournament in succession, with their talented squad rarely displaying their full potential in Morocco, while Pape Thiaw's Senegal will remain in Tangier for a heavyweight showdown against Egypt or the Ivorians.
