The Cheetahs lived up to their favourites tag in the encounter as they dominated proceedings and got the opener through Slovakian international Vladimir Weiss in the 36th minute from the penalty spot after Ghanaian-born Qatari international Razak Mohammed was fouled in the box.
Mohammed Razak doubled Al Gharafa lead in the 38th minute after he was fed through by Weiss.
Al Gharafa will now await the winner of the game between Al Sailiya and Al Khor in the semi finals.
Sumaila will be hoping to clinch the title again after helping Kuwaiti side Al Qadsia annex it in his first season.