Inglis led all 25 laps of the Friday night feature, but won the race by just half a car length to the defending Australian champion Jock Goodyer in a grandstand finish.
In a surprise win, Inglis was shaking his head in disbelief as he performed a wing dance with the checkered flag in front of the monster Warrnambool crowd, admitting it was the biggest victory of his career.
“Just to be getting a trophy on this night is huge, but to win it is just amazing really – I'm thrilled,” Inglis told Speedcafe.
“I just wish it was [Saturday] night, it's a bugger we have to come back and do it all again tomorrow now!”
Starting second on the grid, Inglis held his nerve despite a number of red flag stoppages throughout a bruising final played out on a difficult Premier Speedway surface.
On one red flag Inglis had been passed by Goodyer and Brock Hallett, but the positions didn't count after the stoppage.
“It was a treacherous track – you had to go flat out but it was bumpy in parts and lightning slick in other spots, so it tested everyone,” Inglis said.
“It hasn't been my best season, and we really struggled here last week at the Classic, so this will do wonders for my confidence ahead of tomorrow.”
Inglis and Goodyer were joined on the podium by the in-form Hallett, who won Wednesday night's Presidents Cup at Avalon and finished second last Sunday in the Grand Annual Sprintcar Classic.
Lockie McHugh and Jamie Veal rounded out the top five.
Veal was part of the biggest moment of the race, in a fierce battle with fellow Warrnambool racer James McFadden for fourth position.
It ended with the popular World of Outlaws race winner riding out a vicious crash in turn one, continuing his dreadful run of outs across the summer.
It had been a brilliant run by McFadden, who had moved his way through the field from a 13th starting position to be running fourth, before his incident.
McFadden is now 15th in points and has an enormous task ahead of him tomorrow if he's to claim a third National Title.
The hard luck story of the night belonged to Supercars' rising Sprintcar star Cam Waters.
The Tickford racer continued his stellar dirt form this month, winning a heat and qualifying sixth for the feature – only to have a mechanical issue rule him out before even taking the green flag in the final.
Saturday night will see the bumper 80-plus car field have a final round of heats, culminating in the 40-lap final for the right to be crowned Australian number one.