It was the first goalless match so far at the African football showpiece in Egypt, and the 35 degree celsius (95 fahrenheit) mid-afternoon heat was a contributing factor.
However, neither side showed much urgency and there were hardly any clear-cut scoring chances.
After holding Group E top seeds Tunisia, Angola were favourites to win and did get the ball in the net in the final minute only for Hermenegildo Geraldo to be ruled offside.
Mali top the table with four points after two rounds, Tunisia and Angola have two each and debutants Mauritania one.
After a 4-1 hiding from Mali, France-born Mauritania coach Corentin Martins made three changes.
But he kept faith in goalkeeper Brahim Souleimane, who had a shocker against the Malians, standing still as several shots found the net.
Back at the Cup of Nations after a six-year absence, Angola exceeded expectations in their opening outing by coming from behind to draw 1-1 with Tunisia.
But Serb coach Srdjan Vasiljevic still made two changes while once again keeping star winger Geraldo from top African and Egyptian club Al Ahly on the bench.
The countries met in qualifying for this tournament with Angola winning 4-1 in Luanda and Mauritania turning the tables with a 1-0 win in Nouakchott.
In a goalless first half, the best chance to end the stalemate fell to Angolan Djalma Campos, who scored against Tunisia.
Gelson Dala dribbled down the left flank and passed to Campos who rounded Souleimane but his angled, goal-bound shot lacked pace and was cleared by Khassa Camara.
Bruno Gaspar then had a penalty appeal correctly ignored by the Egyptian referee as big-screen replays showed him losing his footing when challenged by Aly Abeid.
Both captains were replaced early in the second half with Angolan Wilson Eduardo coming in for Mateus da Costa and Mauritanian Sounkhasso Diarra replacing Ba Abdoul.
Geraldo also came off the bench, in place of Fredy Ribeiro, but was unable to make an immediate impact on a match offering the small crowd little excitement.
Eduardo had been on the pitch just seven minutes when he wasted a great chance to give his team the lead by poking the ball wide with an open goal in front of him.