Rea had taken pole position in wet conditions on Saturday

The Ballyclare rider came home ahead of Shane Byrne, who was followed by Gregorio Lavilla, Leon Haslam and then Rea's Honda team-mate Ryuichi Kiyonari.

Rea, who lies third in the series on 187 points, was fourth in race one with Haslam winning from Byrne and Lavilla.

Glengormley's Nikki Coates won the 125 race and Adrian Coates won the second of the day's two Superstock events.

Rea described his first-ever Superbike win as "absolutely awesome" but denied that he felt any pressure to win at the Irish circuit.

"We made the wrong tyre choice for the first race so we struggled a bit but the tyre was good for the second race and after a bit of a dice, I managed to break clear.

"I just want to keep closing the gap in the championship, " he said.

Other Irish riders who performed well in the 125 event were James Maguire taking eighth and Nigel Percy 16th.

Adrian Coates crashed out of the first Superstock race while lying fourth but made up for that disappointment by winning the nine-lap second race.

Steve Brogan was the winner of race one, Ballymena's Denver Robb was 14th but Marshall Neill, Alastair Seeley and Stephen Thompson all failed to finish.

In race two, Antrim man Coates won from Glen Richards, Brogan was third, Seeley from Carrickfergus fourth and John Laverty sixth. Neill was 12th and Robb 14th.

The Supersport race saw Padgett's Honda rider Dennis Hobbs take the win ahead of Jamie Robinson and Lisburn's Ian Lowry. John McGuinness and Stuart Easton were fourth and fifth.

Series leader Michael Laverty failed to finish after a tangle with Billy McConnell but the Toomebridge man still leads the championship from Relentless TAS Suzuki team-mate Lowry with Hobbs making up ground in third.