It was a deserved triumph for the Teranga Lions, who overcame a sluggish start to dominate the second half and wasted several chances before securing maximum points. Andre Ayew scored with a penalty on 14 minutes for four-time champions Ghana and 2002 runners-up Senegal levelled through Mame Diouf after 58 minutes.
Several neat touches close to the penalty area created space for Turkey-based Sow to fire past goalkeeper Razak Braimah three minutes into additional time. The much-hyped group of death continues later Monday when top-ranked African team Algeria tackle resurgent South Africa in the second half of a double-header.
Concerns that the tournament in Equatorial Guinea would not draw crowds proved unfounded for the third consecutive day with Estadio Mongomo packed to its 15,000 capacity in hot, dry conditions. Ghana had much more early possession and took the lead when Andre Ayew calmly converted the penalty. Senegal goalkeeper and captain Bruno Coundoul, who conceded the spot-kick by pulling down Christian Atsu, dived to his left as Ayew struck the ball into the middle of the net.
The pace of Ghana was troubling the big Senegal defenders and Atsu almost doubled the lead midway through the opening half. Jordan Ayew burst through the defence and passed for Atsu to beat Coundoul only to see his shot go wide of the far post.
The frustrations of the Senegalese Teranga Lions -- desperate to avoid a third consecutive first-round exit -- showed when playmaker Dame Ndoye was yellow-carded for a late tackle on Atsu.
Strangely subdued Senegal finally sprang to life just before the half-hour as a fierce Kara Mbodj header rattled the crossbar and rebounded to safety with Braimah helpless. Braimah did well to foil Diouf soon after, tipping a spectacular close-range bicycle-kick over at the expense of a corner.
If pace was a Ghanaian weapon, height was an equally potent attacking threat for the Senegalese and it produced an equaliser just before the hour mark. Diouf headed a cross against the woodwork and reacted quickest to nod the rebound into the net and reward early second-half Senegal pressure.
The Stoke sharp-shooter should have scored again midway through the second half, but blazed over from close range when Ghana failed to clear a corner. With ten minutes left, Diouf spurned another good chance to break the deadlock as he pulled a shot wide after breaking through the middle.