John McGuinness dedicated his first TT win since 2009 to his friend Stuart Easton, who was injured in the recent North West 200.
The 'Morecambe Missile' dominated the six lap Dainese Superbike race after Bruce Anstey retired at Quarry Bends, near the Wildlife Park, on the third lap.
With Anstey out, McGuinness led from Guy Martin, until Martin's Suzuki failed him at Hilberry with just over one lap to go.
That left McGuinness with an advantage of over a minute from Australian Cameron Donald going into the final lap.
The comfortable lead was reflected in an average speed of 128.481 miles an hour for his final lap, well below the 130 plus efforts put in by McGuinness, Anstey and Martin at the start of the race.
The overall race time for McGuinness was one hour, 46 minutes and 13 seconds, for a race average speed of 127.870 miles an hour.
Donald brought his Wilson Craig Honda back in second place and Gary Johnson was the third man on the podium, even though he picked up a 30-second time penalty for a pit lane infringement.
Keith Amor made fourth place, despite suffering a bad shoulder injury when he came off during practicing on Wednesday evening.
McGuinness was delighted with his win and told Manx Radio TT listeners it was for his injured friend: