William Dunlop won the all-Irish battle to claim a second success at Billown on Saturday evening.
The Ballymena rider won by 7.4 seconds from compatriot Barry Davidson with another Irishman, Davy Morgan – who was second until late on - managing to hold onto third spot in the 250cc race, despite touring due to clutch problems.
The man from Blackpool, Roy Richardson, also claimed his second victory of the day in the 650cc event.
John Burrows was the runner-up with Czech rider Michal Dokoupil taking third spot.
Dunlop believes Billown suits him perfectly, while Richardson was pleased with the performance of his machine.