Irwin’s BeerMonster Ducati team-mate Tommy Bridewell moved back to the championship summit and holds a narrow lead of 7.5 points ahead of the title decider at Brands Hatch in two weeks’ time.
Bridewell was hit with a three-place grid penalty for Race Three after he barged into Irwin at the Melbourne Loop in Sunday’s opening race, wiping them both out after they had been in contention for victory.
Irwin was also punished, receiving two penalty points for acting in an ‘inappropriate manner’ and ‘interfering with marshal intervention’ as he vented his frustration at Bridewell immediately after the collision.
As the rain came down for the final race, more drama was to follow when Irwin was ruled out with a throttle sensor issue on the first lap.
Bridewell finished the race in ninth to score the PBM team’s only points of the weekend after he and Irwin finished at the back of the field in Saturday’s damp Sprint race.
Irwin, who is aiming to become the first rider from Northern Ireland to win the BSB title, said his objective now is to win all three races at the final Showdown round at Brands in Kent.
“I think there’s a lot of circumstances to the crash earlier on and Tommy showed [his] true colours,” he said.
“There’s a price that’s being paid for it but I felt really good, credit to my team.
“Wet riding was something I had to improve a lot; we had a good warm-up this morning.
“I wanted to get to the front on the warm-up lap and the sighting lap and I felt no limit in the least despite the conditions.
“It’s far from over and I know how I feel at the minute. We can go to Brands Hatch and win three races – it’s not a statement, it’s what we’re going to have to do, and it’s what I can do,” Irwin added.
“I always believe that good things happen to good people, and this team are incredible. I know who the team want to win the championship, let’s put it like that.”
OMG Yamaha’s Kyle Ryde won Race Two from Leon Haslam (ROKiT BMW) and Christian Iddon (Oxford Products Racing Ducati).
In the final race, McAMS Yamaha’s Jason O’Halloran dominated in the wet conditions to win comfortably from Iddon and FHO BMW’s Josh Brookes.
The race was stopped when Haslam’s BMW suffered an engine blow-up. It was a major blow for the former champion’s title hopes, who was running in second at the time with four laps remaining.