There is a huge quality difference

The National team of Senegal is one of the big favourites to win the AFCON 2019 trophy. Based on their performances at the World Cup 2018, they deserved to qualify for the last 16 of the competition. Their players perform at the top European Leagues and they have plenty of experience and quality. Their best defenders are Kalidou Koulibaly and Salif Sane, their top central is Idrissa Gueye, while their big star is Sadio Mane (Liverpool) who had a successful season with the 'reds' and he can definitely make the difference in their attacking line. Undoubtedly their Manager Aliou Cisse has players of world class level in his squad.

On the other hand, Tanzania are not at all famous and they will be probably the weaker team of the 3rd group. Most of their players are performing at their domestic league, except for Mbwana Samata who performs with Belgian Genk. However, that's not enough.

There is a huge quality difference between these two teams, Senegal are definitely the superior ones. Not to forget that this is a FIFA competition and the total goal diference is the first criterion in any tie. So, Senegal have a motive to win with more than one goal difference, and they can do it.