Jamie Whincup has regained the edge in the V8 Supercar title race after clinching both races at the Phillip Island 300.

In a chaotic main race on Sunday, Whincup's Ford led throughout the 44 laps in a flawless display to cross the line ahead of the Holdens of Rick Kelly and Garth Tander.

Will Davison, Whincup's closest challenger in the series, dropped seriously off the pace after finishing in 11th place.

Whincup went into the main race with his confidence already boosted after his victory in race one on Saturday.

And by continuing his dominance over Davison in Sunday's race, Whincup has opened the gap to 122 points with two rounds of the championship left.

The Ford star snared pole position and shot away to open up a four-car gap at the first corner on Sunday before his advantage was almost immediately cut by the first safety car appearance.

The field was brought to a crawl as Ford's Mark Winterbottom was speared off the track at 280km/h after being nudged by young New Zealander Shane Van Gisbergen.

The accident was reminiscent of Cameron McConville's wild spin across the track during the recent Phillip Island enduro - but this time Winterbottom was pulled up by the gravel trap.