A terrible blunder by Guinea goalkeeper Kemoko Camara allowed Mali captain Mahamadou Diarra to score a dramatic injury-time winner to give his side a 2-1 win and a place in the semi-finals of the African Nations Cup on Saturday.
Camara fumbled Diarra's long distance drive and allowed the ball to slip beneath his body and into the net.
The win gives Mali, who had to fight back from a goal down, a semi-final place for the fourth time in four appearances and their second in succession.
They will face either Morocco or Algeria for a place in the final.
Pascal Feindounou had given Guinea a 14th minute lead before Frederic Kanoute hit a first-half injury-time equaliser.
Mali coach Henri Stambouli was full of praise for Tottenham striker Kanoute who has now joined Cameroon's Patrick Mboma as joint top scorer at the tournament with four goals.
"Once again Kanoute found the goal just at the right time for us on the stroke of half-time and that gave us great confidence," said Stambouli.
"He made lots of good things happen for us. But it was a difficult game against a very strong Guinea team.
"It was a collective performance and a victory for all the players, the staff and all of Mali.
"It was a dramatic finale but at the end is the perfect time to score a winning goal."
Kanoute said he was worried that the tie might have been decided in extra-time.
"I was scared about extra-time because tiredness and fatigue mean anything can happen," said the Tottenham star.
"We were a little bit stretched today because we were scared of losing but it was alright in the end.
"It was great to be on the scoresheet again. I want to keep scoring. But I will be just as happy if Mali keep winning."
Guinea coach Michel Dussuyer was a devastated figure and so was his goalkeeper who sat slumped against the foot of his post as Mali players celebrated.
"I am very disappointed. It is a terrible way to lose a match," said Dussuyer.
Stambouli sprang a surprise by leaving out Valencia's Lamine Sissoko in favour of Dramane Traore who had scored in the 1-1 draw with Senegal.
It was Kanoute who had the first chance in the second minute when his firm right foot shot from Soumaila Coulibaly's cross was saved at the foot of the post by goalkeeper Kemoko Camara.
Then a smart Kanoute turn and pass released Traore but the Ismailia striker could only hit a weak shot straight at Camara.
But it was Guinea who took the lead in the 15th minute when Mali defender Souleymane Diamoutene lost the ball on the edge of his own box to Souleymane Youla.
He passed to Titi Camara who in turn squared the ball quickly and smartly to Feindounou and the Bordeaux midfielder coolly slotted the ball past keeper Mahamadou Sidibe for his second goal of the tournament.
In the 37th minute, Kanoute got behind the Guinea defence but his fierce volley was pushed over the top by Kemoko Camara.
In first half injury time, Guinea should have been 2-0 ahead when Youla played a one-two with Titi Camara but he could only hit his shot straight at Sidibe.
He was made to pay for the miss as just moments later, in the second minute of time added on, Mali were back on level terms.
Almamy Bah misjudged a long ball. He allowed it to drop behind him where Kanoute was loitering and the Tottenham man scored with a fine lob over Kemoko Camara.
Both sides had chances to settle the tie in the second half with Kanoute and his former West Ham teammate Titi Camara having the best chances but, again, both keepers pulled off good saves.