After a slow start at the Independence Stadium, the game came to life after Sibusiso Vilakazi came on to replace the injured Thulani Serero in the 25th minute.
Bafana Bafana clicked into gear as Gabuza, who had missed a good opportunity moments before, opened the scoring after finishing a one-touch move involving Tebogo Langerman, himself, Dolly and Vilakazi.
Gabuza got his second from Dolly’s pinpoint cross from the left as he made a near-post run and tapped home to finish a sweeping move, another one the striker started himself by winning the ball high up the pitch.
At this point Shakes Mashaba’s side was flowing with confidence and started to totally dominate The Scorpions, whose chances were restricted by solid defending.
Then Dolly got on the scoresheet, scoring his first senior international goal with a beautiful, first-time outside-of-the-foot shot from 25 yards as the ball nestled into the bottom-left corner.
And the Under-23 captain got his second moments later, controlling and ripping a textbook shot in off the right-hand post, also from around 25 yards.
Bafana’s win keeps their slim hopes of qualifying as a best second-placed finisher alive.
Gambia: Nyabally, Colley, Sanneh, Jatta, K Sambou (Yaffa 47'), G Sambou, Charty, Njie (E Sambou 66'), Drammeh (S Sambou 58'), Jallow, Trawally
South Africa: Khune, Mphahlele, Coetzee, Mathoho, Langerman, Kekana (Furman 72'), Jali, Masango (Makola 64'), Dolly, Serero (Vilakazi 25'), Gabuza