Pre-tournament favourites Senegal dominated possession in the eagerly anticipated encounter and created much of the chances, but the Indomitable Lions weathered the storm and held on for a hair-raising shootout victory.
Aliou Cisse’s side created the first clear-cut opening when captain Cheikhou Kouyate saw his header off a rebound sail narrowly over the bar. Moments later, Sadio Mane cleverly set up Mame Biram Diouf whose lofted ball over onrushing Cameroon goalkeeper, Fabrice Ondoa dropped over the crossbar.
Cameroon gradually clawed their way into the game and in the 35th minute, captain Benjamin Moukandjo forced Senegal keeper Abdoulaye Diallo into a decent save.
The Teranga Lions came off the blocks firing at the restart, Mane setting up Diouf with a teasing cross but the Stoke City striker could only head straight at Ondoa.
Substitute Moussa Sow forced a number of saves from the irrepressible Ondoa as the game ended goalless in regulation time, forcing the first extra-time of the competition.
Jacques Zoua had a golden chance to settle the tie on the 105th minute after being teed up by substitute Vincent Aboubakar, but his shot from six yards was parried by Abdoulaye Diallo to keep Senegal in.
Ondoa, whose heroics have been instrumental in keeping Cameroon in the tournament, became the hero of the shootout as he saved England-based Mane’s spot-kick to send his side through to the semis on a 5-4 victory.
Earlier, two late goals from Aristide Bance and Prejuce Nakoulma handed Burkina Faso a 2-0 win over Tunisia in the first AFCON 2017 quarterfinal at the Stade d’Angondjé in Libreville.
Paulo Duarte’s side will now face Egypt or Morocco in the first semifinal on Wednesday.