William Dunlop claimed his second victory in the Supersport class at the Ulster Grand Prix after a nip and tuck duel with fellow Honda rider Bruce Anstey.
The pair held a commanding lead over Conor Cummins and Lee Johnston at the end of the fourth lap before the race was red flagged due to a crash involving two riders.
With four laps of the scheduled six-lap distance completed, the race was declared a result based on positions at the end of lap three, giving the quiet Ulsterman victory over Anstey (Padgetts Honda) in the first of the day's two Supersport showdowns.
Northern Irishman Johnston, who is a newcomer to the 7.4-mile Dundrod circuit, was credited with a sensational podium finish on the Millsport Racing Honda in third on the count-back.
Tyco Suzuki's Cummins had to settle for fourth position ahead of team-mate Guy Martin, with Michael Dunlop sixth on the Street Sweep/McAdoo Racing Yamaha.
Isle of Man TT Supersport race winner Michael's chances of joining legendary road racer Phillip McCallen in the history books as the only rider ever to win five races in a day at the Ulster GP have now been thwarted.
The Ballymoney rider earlier won the Superstock race on his Kawasaki ZX-10 and remains a slight favourite for the Superbike races at Dundrod.
Lincolnshire's Gary Johnson, who qualified in second place for the Supersport races on the second of the Padgetts Hondas, failed to start the race after his machine developed problems.
Dunlop moved to the front on lap one on the Wilson Craig Honda and led for the entire duration of the race, with Anstey shadowing his every move as the pair opened up an unassailable lead over their main rivals.
It was clearly a two-horse race and Anstey was preparing to make his move in the closing stages before the red-flag situation saw the event halted.
The victory was Dunlop's second international Supersport win this season after he also stood on the top step at the North West 200 in May.
Two riders were involved in the red-flag incident, but both thankfully escaped serious injury.