All four teams in Group B currently sit on a single point following the opening round of fixtures on Thursday.
Mexico registered a 0-0 draw with Korea, while Gabon came from behind to secure a point in a 1-1 draw with Switzerland.
Gabon are taking place in their first Olympic games this year, while Mexico hosted the Olympics in 1968 and are considered as the dark horses for the competition.
Mexico have no fresh injury concerns ahead of the encounter, although Tottenham Hotspur striker Giovani Dos Santos is expected to join Carlos Salcido on the left side of the Mexican attack.
Meanwhile, Gabon are unlikely to make any changes, with Bruno Ecuele Manga and Charly Moussono continuing their role in the side.
Possible lineups:
Mexico: Corona; Jimenez, Reyes, Mier, Chavez; Salcido, Herrer, Aquino, Ponce; Dos Santos, Fabian
Gabon: Ovono; Dinda, Ndong, Engonga, Ndoumbou; Madina, Tandjigora, Bouaaoughou, Obiang; Aubameyang, Nono
Sports Mole says: 2-1