Akram Afif opened the scoring for Felix Sanchez's side, but the West Africans – who were sleep-walking for much of the first period – woke up after the break with stand-in captain Alassane Sylla and Moussa Kone earning them a lifeline. The result ultimately meant Qatar go home, while hosts New Zealand were confirmed of their place in the next round.
Both sides found their chances of progression hinged on clinching three points. Qatar only had hope of a best third-place finish, while Senegal needed to find their scoring boots, which had largely deserted them so far, to earn a top-two place.
After starting out on the back foot, the Qataris composed themselves and found from the spot what they had been waiting over 410 minutes of U-20 World Cup football for. Almoez Ali was dragged down and Afif, who had already threatened, confidently put away the penalty.
Considering what was at stake, neither side really looked to have much fight in them, but after the break Senegal really should have drawn level. A scuffed shot found Mouhameth Sane three yards out, but he fired straight at Yousof Hassan.
Qatar then almost doubled their lead in bizarre circumstances. Senegal keeper Ibrahima Sy, who had been pushing further and further up the field, was caught out by a long punt by his opposite number. Having been beaten by the bounce he had to think fast and head the ball back into his area while under pressure from Ali.
Senegal turned up the pressure and, after coming close, it told. Thiam had been one of the main instigators and pressure from him brought panic in the Qatar area. A poor clearance fell to Sylla and he expertly lobbed Hassan out of almost nothing.
Sprung into life, Sidy Sarr hit an impressive overhead kick wide before Kone headed off target too. But Kone hit the mark a minute later, capping off a flowing move to leave the Africans needing just one to oust Colombia in second. That vital goal almost came from the boot of Mamadou Ndiaye, but his long-range thunderbolt flew just beyond the post, and meant Senegal had to settle for third.