Hearts of Oak fell to a 1-0 defeat to city rivals Great Olympics at Accra Sports Stadium on Wednesday night in week 19 of the 2022/23 Ghana Premier League.
The win takes Bismark Kobi-Mensah's side to 12th on the league log with the Phobians dropping from fourth to sixth.
Slavko Matic's men now have one win in their previous five league games and are now eight points away from the top.
A Glid Otanga penalty conceded from a clumsy challenge offered the Dade boys the opportunity to take the lead from the 18 yard box.
Samuel Ashie Quaye gave the hosts the lead from the spot in the 52nd minute in the Mantse derby.
Olympics held on for their first win in five games, also the first for new boss Kobi-Mensah.
The Dade boys now have four wins in the six previous meetings between these two rivals.
Great Olympics will take on King Faisal in Kumasi in their week 20 fixture on Saturday.
Meanwhile, Hearts of Oak will face one of their toughest test of the season when they come up against Asante Kotoko a day later.