Ian Hutchinson from Yorkshire made the most of Conor Cummins' retirement due to mechanical problems to win the six lap PokerStars Superbike TT by around 45 seconds, from Michael Dunlop, with Australian Cameron Donald third.
Conor, from Ramsey, set a blistering pace from the start and appeared to have a fantastic home win in his sights when he led by 21 seconds going into a pit stop at the end of lap four.
But he lost 17 seconds when the engine of his McAdoo Kawasaki was slow to fire up, and his race came to a premature end at Laurel Bank a few minutes later.
Cummins and Hutchinson put in 130mph plus laps early on, giving the fans fantastic entertainment after the start of the race was delayed by three and a half hours because of sea mist in the grandstand area of the course.
Hutchinson's race average speed was 127.502 miles an hour, as he rode the 1000cc Padgett's Honda to his first 'big bike' win on the mountain course, after three previous victories.
That was inside the race record, but there was some consolation for Cummins as he set a new fastest lap for the event, of 131.511mph, on his first circuit.
Pre-race favourite, and Superbike winner for four of the past five years, John McGuinness, dropped out on the first lap, and a time penalty cost Guy Martin a podium place.