Winterbottom had held the lead since taking it with a victory at Winton in April.
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The 33-year-old has won a total of four races so far this season and is determined to stop Whincup from taking a record sixth title.
“Losing the points lead has definitely given me a kick in the backside and I am keen to get it back,” said Wintebottom, who grew up in Sydney, but now resides in Melbourne.
“It is fitting we are heading to my home track where there will be a lot of friends and family to try and get the lead back heading into the enduros.
“It is a big event this one. I enjoy the circuit so hopefully it is good to us. It could be tough for everyone as there are a lot of unknowns.
“We've had success in the past there and we plan to get the lead back and show that we are in the fight.”
FPR team principal Tim Edwards is wary of the weekend's tight two-day format, which will give teams and drivers minimal time to analyse set-up options on a circuit that has not seen racing action with the Next Generation V8 Supercars.
While pre-season tests at the venue over the last two years have provided some data, rain during last February's test – which also saw FPR lose time running with the incorrect final drive ratios – hampered efforts.
“This is quite a critical event as while it is only two days it is the final hit-out before we head into the Endurance Cup,” said Edwards.
“The condensed format means everyone needs to be at the top of their game as we don't have some of the time luxuries we usually do.
“Our aim is obviously to get the points lead back and put in a strong performance before we head to the big three at Sandown, Bathurst and the Gold Coast as they are events that will shape the championship battle.”
Winterbottom's team-mate Chaz Mostert has performed strongly in recent events, out-gunning his highly-fancied team-mate on several occasions.
Despite his form, the 22-year-old is downplaying the #6 Falcon's chances this weekend.
“My expectations are low this weekend as I haven't raced a V8 Supercar there before,” he said.
“We tested there in February but it was really wet and was my first time in the car. The track is new for a lot of people given we haven't raced there much.”