Michael Dunlop won the Southern 100 Solo Championship title, setting new lap and race records in the process.
The Street Sweep Kawasaki rider won by four seconds from Guy Martin, with Ryan Farquhar a further 2.5 seconds behind in third and William Dunlop fourth.
Michael set a new best lap speed of 112.54mph.
Dunlop also won the opening Superbike race on Tuesday and beat brother William in the 600cc race, while William won the 250cc event.
Martin completed the podium in the 600cc race, followed by Cameron Donald, Dan Kneen and Conor Cummins.
Farquhar enjoyed a Supertwins success.
William Dunlop had to settle for second behind Chris Palmer in the second 125cc race, with Palmer beating Ian Lougher in the first.
Martin took victory in the Senior race on Wednesday night from Michael Dunlop, Farquhar, Cummins and Kneen.
Dunlop edged out Martin by one tenth of a second in Tuesday night's opening Superbike race in Castletown.
Relentless TAS Suzuki rider Martin was in front for seven of the eight laps but Dunlop took victory thanks to a last-gasp effort on the final circuit.
Donald was third, William Dunlop fourth, Farquhar fifth and Kneen sixth.
Donald was 16 seconds behind the leading two riders.
Portadown's Wayne Hamilton won the concurrently run 600cc class, with Davy Morgan second and Lee Vernon third.
Both sidecar races were won by Klaus Klaffenbock and Manxman Dan Sayle.
Simon Neary and Jason Crowe were second and Ian Bell and Carl Bell third on both occasions.