Senegal need a point from their last Group C tie to reach the African Nations Cup quarter-finals after drawing with South Africa while Ghana raised their hopes with a late winner against Algeria on Friday.
Senegal are top with four points followed by Algeria and Ghana on three and South Africa on one with one match to go.
All four countries have a chance to qualify but a draw against Algeria in Malabo on Tuesday will be enough to take the Senegalese through.
Victory for Ghana over South Africa at the same time in Mongomo will also earn them a ticket to the last eight.
Ghana scored two minutes into stoppage time against Algeria to secure a 1-0 victory.
Asamoah Gyan returned from a mild bout of malaria to grab the winner, outpacing Carl Medjani to net from a tight angle.
Ghana, who have reached the semi-finals four times in a row, had lost their opening game in similar fashion to Senegal on Monday.