Burkina Faso and Cameroon advanced to the African Nations Cup semifinals after getting through quarterfinal matches on Saturday.
Cameroon needed penalties to get past Senegal, winning the shootout 5-4 after a goalless 120 minutes.
After both teams were perfect through four rounds of spot kicks, Senegal's Sadio Mane saw his attempt saved by Cameroon keeper Fabrice Ondoa, the Liverpool star then turning and muttering something under his breath.
"We have been studying this Senegal team for a long time," Ondoa said. "I knew that Mane is a great player, he has a lot of great qualities. He is a big player. I have to wait in this penalty. I did not want to jump first and when he moved I tried to follow the path of the ball."
Vincent Aboubakar then stepped up to blast underdogs Cameroon into the last four of the tournament, setting off wild celebrations from the players. Goalkeeper Ondoa leaped over the advertising boards and sprinted to the Cameroon fans, pursued by teammates and even coach Hugo Broos.
Senegal, among the favourites to win after an impressive start, had themselves to blame for their surprise elimination. The team missed chance after chance in normal and extra time, with Mane, Moussa Sow, Keita Balde and Henri Saivet all guilty of failing to convert good chances -- either by missing the target, or finding Ondoa in the way.
Cameroon, missing some big-name players who made themselves unavailable for the tourament, will next play the winners of Sunday's match between DR Congo and Ghana.
Burkina Faso were first into the semifinals after scoring two late goals to beat Tunisia 2-0.
Aristide Bance, with his dyed blond hair, came off the bench to hit a low shot into the bottom corner from a free kick in the 81st minute and break a deadlock.
Bance's introduction, greeted by wild cheers from the Burkina Faso fans, proved to be a masterstroke from coach Paulo Duarte. Bance was a hero for Burkina Faso on their surprise run to the final in 2013 but has been on the bench at this tournament.
"I knew that Bance could get inside that defense and he has a great ability to shoot," Duarte said. "Fortunately for us, the first shot was a success."
Prejuce Nakoulma sprinted away on a counter-attack four minutes after that, avoided a desperate tackle from Tunisia goalkeeper Aymen Mathlouthi way out near the middle of the field, and side-footed into an empty net to seal the game.
Burkina Faso, who lost in the final two tournaments ago, will play Egypt or Morocco in the semifinals on Wednesday. Tunisia lost in the quarterfinals for the second straight time.
Information from The Associated Press was used in this report.