Ugly scenes erupted at Arthur Davies Stadium in the Kitwe derby after Nkana fans threw. missiles on the pitch.
A female assistant referee identified as Nancy Kasitu and a police officer were hit, and needed medical treatment.
Kasitu, a trained Clinical Officer General, COG was in tears as she was attended to by Dr Womba Kadochi on the pitch side.
This match had to be halted for over 15 minutes for security concerns.
The match restarted in the 77 minutes and Kalonji added the second goal.
With three games to go, Power moved to 57 minutes while second placed Napsa Stars are on 49 points.
