Amir Abdou's men have picked one point from an available nine, and they face an opponent still reeling from the concession of a late equaliser against Congo DR.
Match preview
Despite Mauritania's commendable Africa Cup of Nations showing, Abdou has been unable to secure positive results either side of the continental tournament.
The Lions of Chinguetti advanced from the competition's group stage for the first time in the nation's history, having defeated 2019 champions Algeria 1-0 in their final group game.
That triumph was Mauritania's first at the finals, but Abdou's men have been unable to build on that success, failing to score or win their last three competitive or non-competitive fixtures, even if the winless sequence includes a goalless game with Morocco in March.
Losses to Mali and Sudan (both 2-0) either side of that Morocco draw mean the Lions of Chinguetti have fired blanks in four matches in all competitions, dating to their 1-0 loss to Cape Verde at AFCON 2023.
With a wounded Senegal coming to Nouakchott on the back of a point against the DRC, the home support could fear the worst on Sunday.
Aliou Cisse's men were without Sadio Mane against Sebastien Desabre's troops but could and probably should have notched the points in Diamniadio if Nicolas Jackson converted his chance to double the home side's advantage.
Senegal were seeking a seventh straight home triumph in World Cup qualifying, only to be denied by Fitson Mayele's 85th-minute winner, thus leading to another draw.
The upshot of the Lions of Teranga's results leave Senegal in second spot, two points behind surprise leaders Sudan who defeated Mauritania 2-0 in Nouakchott — a similar result for the deposed African champions would be what the doctor ordered.
With Senegal trailing Group B leaders by two points, Cisse's men have little margin for error if they aim to avoid failure to make the 2026 World Cup as qualifying nears its halfway point.
Given Sudan are favourites to defeat South Sudan in Juba, the Teranga Lions hope to avoid the worst scenario after the fourth round of games conclude this weekend.
Mauritania World Cup Qualifying - Africa form:
L
D
L
Mauritania form (all competitions):
L
W
L
L
D
L
Senegal World Cup Qualifying - Africa form:
W
D
D
Senegal form (all competitions):
W
W
L
W
W
D
Team News
Abdou making four half-time changes against Sudan points to multiple changes to the lineup on Sunday.
One Mauritania player expected to start is Aboubakary Koita, and the attacker's incredible ball-striking means he carries a threat of scoring from low-percentage positions.
Ismaila Sarr was tipped to carry added responsibility for Senegal in Mane's absence, something the Marseille forward did all too well last time. Sarr's goal could not win the game for Cisse's men, but the wide attacker is expected to keep his place.
The Lions of Teranga boss is not expected to ring many changes, even if he could demand more from Jackson, Iliman Ndiaye and Habib Diallo to deliver the goods.
Mauritania possible starting lineup:
Niasse; Abd, Yali, Ba, Diaw; Mouhsine, Fofana; Mahmoud, Kamara, Amar; Koita
Senegal possible starting lineup:
Mendy; Seck, Koulibaly, Niakhate; I. Sarr, Gueye, P. Sarr, Diarra; Diallo, Jackson, Ndiaye
We say: Mauritania 0-1 Senegal
Abdou's Mauritania impressed at AFCON 2023 with their organisation and intensity, making them a genuine threat to Senegal despite picking one point from three games.
However, the Lions of Teranga's superior individual quality and the need to secure maximum points to avoid falling further behind give them an added incentive to win in Nouakchott.