TT legend John McGuinness produced a brilliant ride to win the blue riband Senior TT in 2013 and with it claim his 20th Isle of Man race victory.
The Morecambe rider's victory denied Michael Dunlop a record-equalling fifth win of the week.
The race was rescheduled when 11 spectators were taken to hospital after a crash on the opening lap.
Barnsley rider Jonathan Howarth came off at Bray Hill less than a mile from the start.
McGuinness saw off in-form Dunlop by a full 10 seconds to set a new race record, with New Zealander Bruce Anstey in third.
"This is absolutely fantastic," McGuinness, 41, said after the race.
He added: "I thought I wasn't going to win one this week but I pulled it out of the bag. I pushed and pushed and concentrated right until the end. The reception out on track was incredible, there were so many fans out there."
ITV Sport will return for extensive coverage of the 2014 Isle of Man TT races