Viane Ssekajugo and Stephen Mukwala were on target as Uganda beat former Cranes coach and his Zambia 2-0 in a Pre-Chan mini-tournament in Cameroon on Monday.
This follows the 1-1 draw between Uganda and hosts Cameroon last Friday.
Uganda are using this build-up tournament to prepare for Chan 2021 finals that officially kick off on January 16.
The Cranes drew first blood on 25 minutes, finishing off an Ibrahim Orit effort after Zambian goalkeeper Charles Kalumba had spilled it.
The Zambians could have gone into half time level but Zambian forward Paul Katema could only hit the post after beating Cranes goalkeeper Nafian Alionzi.
The Zambians had two more good chances to score after the break, a diving header by Zachairah Chilongosh and substitute Spencer Sautu’s 30 yard effort.
But it is Mukwala who finished off a Cranes attack the other end after dummying the Chipolopolo goalkeeper twice for number two.
McKinstry made six changes in different intervals after the break as he continued trying to give everyone a chance to show what they can offer.
The Cranes wrap their build-up tourney with a clash against Niger on Thursday.
Uganda are pooled in Group C alongside defending champions Morocco, Rwanda and Togo.