The meeting of an unusual-looking top-four clubs produced a memorable victory for Citizen and an equally memorable low for Kitchee, as the former beat the latter 2-1 at Mongkok Stadium, while leaders Sun Hei failed to win for the third match in a row as they were held 1-1 by second-placed Buler Rangers.
Ma Shuai, Citizen's on-loan striker from Dalian, scored once in each half to help his side consolidate their position near the top of the table in their first season in the top flight.
Szeto Man-chun pulled on back with a spectacular strike from long range but Kitchee never looked like drawing level in a match where the coach's and players' moods contrasted hugely.
'This is our best game of the season,' said Citizen's Simon Chan Kung-hing.
'I think we played our worst game this season; no skills!' complained Kitchee's Ricky Cheng Siu-chung.
'It's marvellous. It feels great to beat Kitchee. We're so united, we try together to win every match. That was the difference - every player on our team is so determined and confident,' exclaimed Citizen's goal hero.