In a sensational Isle of Man TT first practice, Michael Dunlop threw down the gauntlet to his Lightweight opponents by unofficially breaking the class lap record on his first outing on the Italian built Paton machine to top the timesheets and was also second fastest to Dean Harrison in the Supersport class.
Perfect weather conditions greeted competitors who took full advantage of two hours of track time for the two classes, Harrison racking up six laps on his Silicone Kawasaki and setting the only sub-18 minute lap in Supersport on his fourth lap with a time of 17m 59.743secs, a speed of 125.797mph while Dunlop weighed in with a 125.741mph on his third lap, half a second behind the Yorkshire man.
Ivan Lintin set a scorching pace in the Lightweight class, eventually settling for a 120.660mph some 23 seconds clear of Derek McGee on his IEG KMR Kawasaki.
After an exploratory lap, Dunlop speeded up to 118.952mph on the Paton, which was so impressive at the North West 200. Then, after adjustments relegated McGee to third, he upstaged everyone with a 120.875mph lap, two seconds faster than Lintin and a quarter of a second unofficially inside James Hillier's current lap record.
Some eight seconds back in third was the impressive McGee, the best of Ryan Farquhar's four-man IEG KMR Kawasaki team that had Peter Hickman fourth, late addition to the team Aussie Dave Johnson sixth fastest and Danny Webb ninth.
Manxman Conor Cummins was first to complete a lap in the 2018 TT, ending up in the Supersport class in third behind Harrison and Dunlop on 125.152mph, the only three riders to surpass the 125mph mark in the Supersport class. Dan Kneen, Hickman and Lee Johnston completed the top six in Supersport with James Hillier, William Dunlop, Josh Brookes and Lintin rounding out the top 10.
On his first laps back on the Mountain Circuit following his Senior TT accident a year ago, Ian Hutchinson was 15th fastest on the Padgetts Honda with a speed of 121.327mph.
Huthinson said: "I was feeling a bit tense, but the track was good and I got what I needed, putting in a good few laps."
This evening's practice will see the Superbikes and Superstock machines take to the circuit for the first time from 6.20pm alongside the Supersport and Lightweight machines.