Ashanti Gold, who are tied with third-placed Asante Kotoko on 21 points, suffered a humiliation at the hands of Academy Boys.
Konadu Yiadom and Daniel Owusu each grabbed a double for WAFA, while Andrews Ntim and Ibrahim Abukari added the remaining goals. Amos Kofi Nkrumah scored for AshGold to briefly make the score 1-1.
At the Carl Reindorf Park in Dansoman, Elvis Kyei Baffour's 65th-minute strike spurred Liberty Professionals to a 1-0 home victory over second-from-bottom Karela United. The Scientific Soccer Lads have moved to 10th on the log.
In Cape Coast, Ebusua Dwarfs, third from bottom of the table, were held to a 0-0 draw by visiting Inter Allies, who occupy the 11th position.
Medeama will host Great Olympics in the last game of matchweek 12 on Monday.
RESULTS
‣ WAFA SC 6-1 AshantiGold SC
‣ Chelsea 4-2 King Faisal
‣ Liberty 1-0 Karela Utd
‣ Ebusua Dwarfs 0-0 Inter Allies
‣ Hearts of Oak 1-1 Elmina Sharks