Simon Hodge and Justin Ruggier extended their leads in the Formula 3 and Kumho V8 Touring Car title races respectively on the penultimate day of the Shannons Nationals season.
All classes had to brave wild weather at Sydney Motorsport Park as electrical storms lashed the circuit throughout the day.
Hodge demolished the seven-car field in F3's opening nine-lap heat, leading every lap from pole to win by nine seconds.
While title rival Ben Gersekowski took second, Hodge needs just nine points from the final two races on Sunday to seal the title.
“There's a lot of pressure coming into a weekend, a showdown like this and to execute the way we did today is a great way to generate confidence going into the business day of the season tomorrow,” said Hodge.
“The start was tricky because it's downhill here and I was learning on the fly, heel-toeing trying to keep the brake on and the revs up – but it worked well even though I've never experienced anything like it before.”
Garnett Patterson beat Ricky Capo to the National Class win with third outright ahead of Nathan Gotch, Roland Legge and Dennie Rumble in the three Kumho Cup entries.
Chris Anthony failed to take the start after a crash in qualifying but is expected to return to the grid on Sunday.
In the Kumho V8 Touring Cars, Justin Ruggier now holds a 52 point lead over Ryan Simpson after taking victory in Race 1 of 3 for the weekend.
Ruggier took pole by 0.6s from Simpson before splashing his way to a three second win in the race's wet conditions.
The result puts Eggleston Motorsport Holden driver Ruggier in a commanding position for the title, with a maximum of 100 points available on Sunday.
Series returnee Jose Fernandez qualified third for Race 1 but, without a set of wet Kumhos on hand, struggled home as the last of the finishes in seventh.
Matthew Palmer, Matt Chahda, Brendan Strong and Darrin Renouf filled third through sixth at the flag, while Steve Briffa and Chris Delfsma both retired with mechanical problems.
Today's two Radical Cup race wins were shared by Michael Shaw and Peter Johnston.
Shaw benefited from a mid-race Safety Car, triggered by the arrival of the storm, to win Race 1 before an early collision left the SR3 class leader seventh in the second heat.
The opening race of the Formula Ford Series' penultimate round saw Jordan Lloyd take victory.
Lloyd overtook early leader Thomas Randle on the fifth of nine laps before pulling away to a comfortable win.
Randle, who missed Friday practice due to Year 12 exams, finished second from Nick Rowe, Hamish Hardeman and points leader James Goulding.
Tony Ricciardello meanwhile made a strong start to his weekend with pole for the Kerrick Sports Sedan finale.
The West Australian, who only needs a handful of points to secure an eighth title, proved 0.8s quicker than long-time rival Darren Hossack.
The PRB Clubmans are also on the bill at the Shannons meeting, but had their first race called after just one lap to due the weather.