The title holders have suffered a lone goal defeat to the Mauve and Yellow boys in a week six GPL outstanding clash staged in Tarkwa Akoon Park through a goal from their ex-star Vincent Atingah.
Hearts of Oak dominated the game with a free flowing football and had a close chance to take the lead during the 19th minute but the opportunity was squandered by Daniel Afriyie Barnieh.
Coming back into the second half, Medeama nearly had a goal with a powerful shot from Toure but was superbly saved by Ayi.
Both sides opened up looking for a lead but it was hard to make amend.
Medeama SC later snatched the long and awaiting goal following a penalty decision from the referee which was calmly converted by Vincent Atingah after sending Ayi to the wrong direction.
The victory sends Tarkwa boys to the 4th position before their week 13 match against Great Olympics on 16 January. The Phobians will play Eleven Wonders in their next fixture at home.