The victory completes the double for Kotoko over their arch-rivals, following a thrilling 3-2 win earlier in the campaign.
Mukwala, who was also on target in the previous encounter, led Kotoko to a 2-0 win at the Baba Yara Stadium on Sunday afternoon with his double strike.
Both teams have struggled this season, but Kotoko came into the game slightly superior, two points ahead of Hearts of Oak, and they proved their dominance with a superb display.
Mukwala opened the scoring in the eighth minute, outpacing his markers to latch onto a long ball and controlling it well before slotting it in for the Porcupine Warriors.
He sealed the win in the 95th minute with a brilliant effort, cutting inside from the left and unleashing a shot that beat the goalkeeper.
The Ugandan striker received a yellow card for excessive celebration after removing his shirt.
The win propels Kotoko into the top half of the table, now in 9th place and further away from the relegation zone.
Meanwhile, Hearts of Oak find themselves in a precarious position, sitting 14th on the table, just two points above the drop zone.
They face the risk of relegation if they do not improve in their final three games of the season—a shocking prospect for a club with their storied history as one of the biggest teams in Africa.
