The Ulsterman ended practice week the fastest rider of all with an unofficial lap record of 135.531mph, with Dunlop also leading the Supersport times in qualifying.
Dunlop was only briefly headed in the four-lap contest, before ultimately winning by 12.3 seconds from Peter Hickman.
The race was delayed by three hours owing to a serious road traffic accident on the mountain this morning, but eventually got away at 2:45pm local time.
David Johnson led the field away on his Jackson Racing Honda, but was quickly overhauled by number two starter Dean Harrison on the Russell Racing Yamaha.
Harrison led by 0.550s from Dunlop through the first sector split at Glen Helen, with Hickman slotting into third.
Dunlop took the lead at Ballaugh Bridge by 1.5s from Harrison, and continued to swell his advantage to 5.4s as he screamed through the start/finish straight on his 600cc MD Racing Yamaha.
Posting a lap of 128.3mph from a standing start, Dunlop threatened to set a new class lap record as he swelled his lead to 13.4s by the end of lap two.
Dunlop had a marginally slower pitstop for fuel at the end of lap two than Harrison and Hickman, but it didn’t cost him much.
Through Glen Helen on lap three Dunlop’s lead was down to 11.1s, but was soon back up to 12.1s through Ballaugh and stood at 17.5s come the end of the tour.
Dunlop led by 16.7s through Glen Helen on the final lap, but eased off through the tour to get to the finish safely for his 10th win in the Supersport class.
Now on 22 TT victories, Dunlop is just one away from moving into second on the all-time winners’ list and joining John McGuinness – who is not competing in the Supersport class this year – on 23.
The battle over the final two laps became for second as Hickman began to reel in Harrison on the leaderboards.
Starting lap three 10.5s clear of Hickman, Harrison was just 4.8s ahead through Glen Helen on the fourth tour.
Hickman, who admitted it took him too long to get up to speed on his 765cc Trooper Triumph, cut the gap down to 0.189s through the Bungalow section.
At the finish, Hickman managed to snatch second away by 0.394s, with Harrison settling for third on his first race on the Yamaha R6.
Hickman ended up with a lap closest to the class record on his final tour, posting a 129.039mph effort - just over 1mph shy.
Fourth went to KTS Racing’s Jamie Coward, who was 41.2s behind Harrison, with Davey Todd completing the top five on his Padgetts Racing Honda – 2.8s behind Coward.
Picture credit @ttracesofficial/Pacemaker Press
