A thrilling opening Supersport race at Armoy went to William Dunlop after one of the closest finishes ever at the popular Irish National meeting on Friday evening.
Dunlop led for most of the race but had to fend off a late challenge from his brother and 13-time Isle of Man TT winner Michael, who began the final lap 0.9 seconds adrift.
However, the 27-year-old closed the deficit around the three-mile course and managed to squeeze ahead briefly on his Yamaha R6, only for William to edge back ahead on his own Yamaha as the pair went head-to-head at their home meeting.
Only 0.007 seconds separated them at the line as the elder of the Dunlop brothers claimed his third straight win in the Friday evening race at Armoy.
Dublin rider Derek Sheils finished third on the Cookstown B.E. Racing Honda ahead of Manxman Dan Kneen on the Mar-Train Yamaha.
Derek McGee, who clinched pole position in practice, didn't start the race but is expected to be in action again on Saturday.
In the Superbike class, Michael Dunlop took pole on his MD Racing BMW as he attempts to win the feature 'Race of Legends' showdown for a record sixth time.
Dunlop topped the times from Sheils and McGee, with William Dunlop fourth fastest on his MMB Yamaha R1.
Armoy is the final Irish roads meeting before the MCE Ulster Grand Prix at Dundrod, which takes place from August 10-13.