Mauritania coach Corentin Martins has described the Africa Cup of Nations clash against Tunisia as a "final" with both teams looking to qualify for the last 16.
Mauritania are bottom of Group E but can still make the knockout stage with a victory over the Carthage Eagles.
The tournament debutants claimed their first ever point of the competition with a 0-0 draw against Angola but need three points from Tuesday's game to progress.
"We have one more match and it's going to be against Tunisia," Martins told goal.com. "It's going to be a final for us and we hope to roll out a great performance."
Despite being the second-highest ranked nation in the competition, Tunisia could only manage draws against Mali and Angola meaning they also need a victory to guarantee a place in the last 16.
They are ranked 78 places higher than Mauritania but are under growing pressure to live up to expectations.
Manager Alain Giresse addressed calls for him to play midfielder Ferjani Sassi, the only Egypt-based player in the Tunisia squad, following his side's 1-1 draw with Mali.
"I thank God that there is no more than one Tunisian player playing in the Egyptian league because in this case, I will have to involve every player whose name is called in the stands," the French coach said.
"Ferjani Sassi is returning from injury and needs rehabilitation in order to return to his full level."
