Mali beat Ghana to finish third at Nations Cup
The giant France-based striker scored both from close range as Mali ensured a second successive crushing defeat for Ghana, upset by Zambia in Wednesday's semi-finals, in four days.
Ghana's misery included the dismissal of central defender Isaac Vorsah for a second yellow card just past the hour mark.
Diabate put Mali ahead when he was first to react after goalkeeper Adam Kwarasey could only palm out a long-range shot in the 23rd minute, sliding the ball into the net.
He added the second with 10 minutes left after a breakaway ended with a pinpoint cross from full-back Adama Tamboura.
Diabate is level on three goals with six other players at the top of the tournament's scoring chart.
A dispirited Ghana saw Vorsah become their third player to be sent off at this year's finals.
Ghana, who had beaten Mali 2-0 in the group phase last month, thought they had scored just after half-time but Sulley Muntari's effort was ruled offside.