Dubliner Derek Sheils won the Enkalon Trophy for the third time at Bishopscourt on Saturday.
The event was run over two legs and Gerard Kinghan won the first race from fellow Kawasaki rider Sheils, with Alastair Kirk third.
Sheils took the victory in race two, coming home ahead of Kirk and Crumlin's Stephen Thompson on a BMW, followed by Kinghan in fourth.
William Dunlop was a double Supersport 600cc winner on his CD Racing Yamaha.
Jamie Patterson finished runner-up in race one and Robert Kennedy second in race two.
Former British 125cc champion Christian Elkin took the chequered flag in the two Supertwins outings.
Female competitor Melissa Kennedy took victory in one of the Moto 3 races.
Sheils secured his third Enkalon Trophy success after victories in 2004 and 2013.
The Irish championship shirt circuit action continues at Kirkistown on Easter Monday, with the Mayor's Trophy the feature event.