Zanaco failed to consolidate their stay at number four on the FAZ Super League table after losing away to Buildcon on Wednesday in a rescheduled FAZ Super League Week 25 fixture.
The 2020/202 runners-up lost 2-0 away at Levy Mwanawasa Stadium in Ndola to 10th placed Buildcon.
Lubinda Mundia put Buildcon ahead in the 14th minute and Christopher Chola added the final goal in the 30th minute.
The result now sees Zanaco, who drop to fifth, exchange places with Nkana on goal difference and tied on 49 points heading into the final day of the season on May 8.