Cameron Donald followed up Friday's two wins at Bishopscourt with a four-timer on Saturday.
The The Wilson Craig-sponsored Honda rider from Australia won the feature Enkalon Trophy race, ahead of Kirk Jamison and Michael Dunlop.
Donald also secured victory in the Irish Superbike race and the two Supersport 600 races.
William Dunlop won the two 250 events while Paul Robinson and Korie McGreevy were 125 winners.
Matthew Percy and Stephen Thompson completed the podium places in the Irish Superbike round while Thomas Lawlor was runner-up in both 250 races.