Mark Winterbottom saw his title hopes take a knock in the Falken Tasmania Challenge at Symmons Plains Raceway this weekend as arch rival Jamie Whincup managed to extend his lead.

Winterbottom finished fourth overall in his Ford Performance Racing Falcon behind title rival Whincup - who took the round win - but with only one event left, the 233-point gap now looks daunting.

'Frosty' was battling at the front all weekend and thirty laps of defensive driving in today's first race almost secured him his second top three finish. Craig Lowndes was relentless, however, and made the pass for third with two laps to go.

In the third and final of the weekend, Winterbottom made a great start in the Orrcon Steel Ford Credit FPR Falcon to pass Todd Kelly but the pit stops undid his hard work and the Holden man took the place back.

"You'd like to think we could still win the championship but it's unlikely," Winterbottom confirmed. "Jamie's doing a good job; you can't fault the team. Craig Lowndes made it easier for him this weekend by protecting him on track so he had no pressure.

"Obviously 888 has found something because both cars have upped their speed; they're just so dominant but in that last race our car was probably as good. If I'd have got Todd [Kelly] I would have been more with it but I just couldn't have a go. I went deeper and deeper into the corners but never really found the limit."

After a none-finish on Saturday, Steve Richards meanwhile drove through from the back of the grid in the sister car to run 14th in race 2. Some gutsy passing manoeuvres came to nothing, however, when the category-specified Motec CDI unit failed, forcing him to retire six laps from the chequered flag.

Starting from the back again in the third race, Richo persevered and made his way up to 17th.

"The car was fantastic; the changes we made were probably a little bit more out on a limb than we would normally make but it was definitely the right decision," said Richards.

"Starting from the back just means you're in a queue of cars, your brakes are hot and it's very difficult to pass. You make your way through and then something out of your control scuppers your effort! You feel disappointed for everyone not just yourself."

"The car was great and both drivers had really good speed in the last race," summed-up FPR team boss Tim Edwards. "The changes we made improved it but unfortunately we needed to have that car two races ago. It's important that we learnt something but overall it's pretty disappointing."