Ghana virtually through to the knockout stage of the 2012 African Cup of Nations but had to endure another slow start against Mali on Saturday in Franceville.The Black Stars beat the Malians 2-0 in the second Group D clash to go three points clear at the top but have to wait until the final matches on Wednesday.After a goalless first half, Asamoah Gyan and Andre Ayew scored to seal victory at the Stade de Franceville with the Black Stars striker haling the win as crucial."This was a very important victory and we hope to continue to make Ghana proud," Gyan said after the game.And the victory capped yet another slow start by Goran Stevanovic's side but Gyan says a change of tactics turned things around."We had a few difficulties in the first half, but the boys showed strong character and we changed tactics and put pressure on them to make mistakes in the second half," said Gyan.Ghana plays Guinea next on Wednesday to complete the group fixtures.