Dean Harrison clinched his maiden Southern 100 Solo Championship crown by taking victory in Thursday's thrilling nine-lap race on the Billown circuit.
Silicone Engineering Kawasaki rider Harrison edged out runner-up, Manxman Dan Kneen, by 0.131 seconds, with Michael Dunlop third on his Suzuki.
Dunlop set a new absolute lap record with an average speed of 115.707mph.
Harrison took a hat-trick of wins over the course of the meeting, with Dunlop also securing a treble of victories.
Harrison, Dunlop and BMW pilot Kneen each enjoyed spells at the front as they traded positions regularly throughout the feature event.
"I've been trying to win that race for five years and I'm over the moon," said Bradford man Harrison after his 'big race' success.
"Everyone is pushing really hard so it's a hard race to win. The lead swapped and changed a few times but I just kept braking as late as I could and kept the head down.
"I had some bad luck issues with the bike over the last few days and missed two races but this makes it all worthwhile," added the Yorkshire rider.
Dunlop on form in Superbikes
Earlier in the day, Dunlop, 28, surpassed the previous best lap benchmark with a speed of 115.267 in winning a keenly fought Senior race.
The Ballymoney man enjoyed an advantage of less than a second over Kneen at the chequered flag, with Jamie Coward completing the podium, some 25 seconds behind Dunlop.
Harrison won the 600cc opener on Wednesday and then got the better of runner-up Dunlop and third-place finisher Cowton in the second event for that class on Thursday, Dunlop having the consolation of a new lap record at 111.335.
Ivan Lintin took a slender triumph over Cowton in Thursday's Supertwins outing to complete a double in that class, Rob Hodson occupying the final rostrum position.
Ballymoney's Darryl Tweed made it two wins from two by ending 5.6 seconds in front of Seamus Elliott in the 400cc/125cc, with Paul Gartland third.
In the Sidecar Championship race, John Holden and Lee Cain were declared the winners over Wayne Lockey and Mark Sayers, after brothers Ben and Tom Birchall and Tim Reeves and Mark Wilkes crashed at Cross Four Ways while battling for the lead.
The Birchalls set a new lap record for the class at 101.545mph.