Manxman Dan Kneen repeated his success of 2014 in the Tandragee 100 feature race, taking victory from Derek Sheils and Bolton's Malachi Mitchell-Thomas.
Earlier in the day, Kneen came in first in the Open race but he and runner-up Derek Sheils were penalised one minute for allegedly jumping the start.
That left Ryan Farquhar the winner but the result is the subject of an appeal.
William Dunlop took the 600cc honours, Farquhar was the Supertwins victor and Sam Wilson took the flag in the 125cc.
Welsh competitor Rhys Hardisty edged out Saintfield's Davy Morgan by 0.2 seconds in the 250cc event.
The outcome of the five-lap Open race was left shrouded in controversy, with the definitive winner of the event still to be decided.
As it stands, Farquhar won from Dunlop and Mitchell-Thomas, but the stewards of the meeting are set to look at the circumstances surrounding the outcome again.
The penalties incurred by Kneen and Sheils saw them relegated to 10th and 11th places respectively.
Kneen, a double winner over the 5.3-mile course on his debut two years ago, produced a commanding performance in the feature event, beating Sheils by more than six seconds.
CD Racing Yamaha rider Dunlop, 30, came home 1.2 seconds ahead of Mar-Train Yamaha pilot Kneen at the flag in the 600cc class after a thrilling battle at the front.
Mitchell-Thomas, the hat-trick hero at the Mid Antrim 150 three weeks ago, occupied the final podium spot for the Cookstown BE racing outfit on his Honda.
Farquhar lapped up the perfect conditions to triumph in the Supertwins race, seeing off Mitchell-Thomas in an exciting finish, with Sheils in third.
Czech visitor Michael Dokoupil was a popular winner of the 400cc race, securing victory by two-tenths of a second over Farquhar, who was on board his single cylinder 450cc Kawasaki.
Wilson was followed home by Adam McLean, Paul Robinson in the 125s, while Gary Dunlop, son of the late Joey, was sixth on his Tandragee debut.