The top five teams in the MTN Super League all won at the weekend, but defending champions Red Arrows were the big losers as they fell seven points behind leaders ZESCO United following a 1-0 defeat to the latter.
ZESCO have 46 points from 24 games, two more than Kabwe Warriors in second place, and a further two ahead of third-placed Power Dynamos.
Nkana and Nkwazi both have 40 points.
Pasco Phiri scored the only goal of the game as ZESCO defeated Arrows to show their championship credentials.
Warriors were also 1-0 winners as they edged Zanaco thanks to a strike seven minutes from fulltime by Simon Tonga.
Power Dynamos claimed a 2-0 victory at Atletico Lusaka to keep their title chances alive as Fredrick Mulambia and a penalty from Brian Masanyinga gave them the points.
Nkana defeated 10-man Green Eagles 1-0 as Clement Mwape's goal on the stroke of halftime proved the difference.
Nkwazi defeated Nchanga Rangers 2-1 as they had to come from behind for victory.
Elliot Kampukesa put Rangers in front just before the half-hour mark, but goals from Misheck Luwisha and Innocent Kashita turned the game on its head in favour of Nkwazi.
Bornwell Mwape scored the only goal of the game as Green Buffaloes won 1-0 at FC MUZA and Jimmy Mukeya got an early strike as NAPSA Stars edged Mufulira Wanderers by the same scoreline.
Lumwana Radiants and Forest Rangers played to a 1-1 draw.
Chris Mugalu put Rangers ahead, but an injury-time equaliser from Benjamin Mukanda rescued a point for Radiants.