Into Ramsey now and Harrison's lead is down again to 4.050s.
That battle for third is well on its way to being Hillier's, as he is now 5.3s clear of Todd.
Through Ballaugh, the lead has come down slightly. Harrison is now 5.595s ahead of Dunlop.
Hillier was third into the pits, 1.187s clear of Todd. So that battle for third remains tight and is still going Hillier's way right now.
So, Dunlop has gained a second but that won't be enough to challenge Harrison right now.
Harrison's stop was 32.6s, Dunlop's 31.6s.
Small fork tweak for Dunlop and away again.
Only fuel for Harrison in this stop, no new tyre. Dunlop is 7.4s down into the pits.
Harrison posts a 127.888mph on lap one into the pits.
We'll see if this pace for Harrison and Dunlop is a difference in fuel at the stop. Harrison may well be on lower fuel but will need a longer stop while Dunlop could be on a heavier load to have a shorter stop.
Through the Bungalow, Harrison's lead has grown to 6.532s over Dunlop, while Hillier is 1.5s ahead of Todd in third.
Paul Jordan, who was first on the road at the start, has stopped.
Michael Evans is up to fifth ahead of Mike Browne, Josh Brookes, Rob Hodson, James Hind, Ian Hutchinson.
Hillier holds third through Ramsey, 0.416s over Todd.
Harrison is really on it here. He's 5.073s clear of Dunlop at Ramsey.
Hillier has dropped 2s behind Dunlop and is only 0.033s ahead of Todd at Ballaugh.
Harrison has extended his lead at Ballaugh to 4.6s over Dunlop.
Great start for Hillier. From having no ride a few months ago to running third early on the Kawasaki, which has been granted a few hundred extra rpm by the organisers.
Supersport is Harrison's class in BSB this year, so this should be his best class at the TT in theory.
He's made a quick start in this race.
Davey Todd, the Superbike TT winner, only fourth through Glen Helen. Hillier third on the Kawasaki currently.
Through Glen Helen on lap one and Harrison leads Dunlop by 3.4s.
Dunlop didn't look too stable on that Ducati through Gorse Lea. Needed a couple of stabs to get the front turned in through the fast right.
Dean Harrison has already caught David Johnson on the road. So, that's 10 seconds gone already before Glen Helen. He's up for this today is Dean!
Lots of questions in practice on whether Michael Dunlop would race the Ducati in this class after some teething troubles. But he's on his way on that Panigale and he'll be one to watch.
This has been his class for the last few years.
Paul Jordan is on course to start the Isle of Man TT Supersport 1 race.