Eaglesham (Edinburgh University) won gold in the 50m, 100m and 200m freestyle, plus the 50m butterfly.
The 200m ended the hat- trick hopes of world open water champion Keri-anne Payne. Winner of the 800m and 400m freestyle, the two-time Olympian could only finish fifth, more than three seconds behind Eaglesham's 1:58.69.
McKenzie is just 16, but she underlined her talent by claiming all three backstroke titles and setting two Scottish records. The second came last night with a 100m time of 1:00.20.
Dan Wallace won the 400m individual medley (4:10.35) and the 200m freestyle (1:47.42) with South Aberdeenshire's Kerry Buchan taking the 200m breaststroke in 2:25.89.
Suleman Butt (Aberdeen) set British junior records in the 60m and 100m freestyle and the 100m individual medley and collected a bundle of Scottish junior titles.
n In Istanbul, Swansea's Jemma Lowe claimed her second medal of the World Short-Course Championships when she was third in the 100 metres butterfly. Then Fran Halsall (Loughborough) went one better with silver in the 50m freestyle.