None of the teams who have qualified for this year's World Cup has won a game yet, with Cameroon, Algeria and Nigeria losing their opening matches and Ivory Coast being held to a draw.
Ghana play their first game in the tournament on Friday against Ivory Coast in Group B.
Cameroon, who pipped Gabon in the race to a World Cup spot last November by finishing ahead of their neighbours in African qualifying, take on Zambia and Gabon face Tunisia in the group's next match day on Sunday.
In a game featuring two French coaches, former international players Paul Le Guen and Alain Giresse, the Indomitable Lions got off to the better start.
In the eighth minute, Achille Emana saw off two defenders before firing a fine shot that was deflected on to his post by Gabon keeper Didier Ovono.
The 33-year-old Rigobert Song, who is taking part in a record-equalling eighth Nations Cup finals, looked his age nine minutes later when he let Roguy Meye find Daniel Cousin with a through ball.
The Hull City striker then coolly slotted home to open the scoring against the run of play.
Cameroon piled on the pressure with Geremi unleashing a powerful 25-metre drive parried away by Ovono.
Inter Milan striker Samuel Eto'o, who is looking to set a new scoring record at a single Nations Cup, failed to live up to expectations and was barely a threat to the Gabon defence.
Cameroon coach Le Guen replaced midfielder Landry Nguemo with forward Somen Tchoyi at halftime but the substitution did not pay off.
Geremi again found Ovono on his way two minutes from time when his powerful free kick was tipped over the bar by the Gabon keeper.
Gabon could have made it 2-0 in stoppage time but Willy Aubameyang's 30-metre free kick smashed the bar and bounced out in front of Idriss Carlos Kameni's line.
Gabon coach Alain Giresse, however, was quick to put things in perspective.
"It does not write off our two defeats (against Cameroon in the World Cup qualifiers). You do not play to try and change the past," he said.
"We had set up a tactical frame to counter Cameroon's game and it worked out."
