Frosty fires in final practice

Championship leader Mark Winterbottom has topped the final practice session at the Wilson Security Sandown 500.

While his teammate Chaz Mostert looked set to take out the session, 'Frosty' recorded his 1min08.87 in the dying seconds, proving the Prodrive Falcons should be the ones to beat in qualifying this afternoon.

Qualifying runs across three sessions at Sandown today, with an all-in session determining a race grid for a 60km co-driver sprint, followed by a 60km primary driver race to set tomorrow's starting positions.

The 40-minute pracrice session was the last opportunity to tweak the V8 Supercars before qualifying - and reigning Sandown winner Jamie Whincup slotted into third after recording yesterday's quickest time.

Scott Pye came home fourth, with stand-in primary driver Jack Perkins completing the top five.

Perkins pairs with Russell Ingall, who raved about the improvements the team made overnight.

"The car's a lot better today - we had a pretty intense debrief last night and one thing about this track you've got to have a good car and that's over the kerbs, you have to fly over them nicely," Ingall said.

"It almost feels like setting the car for a street circuit... when it's comfortable and easy to drive all of a sudden you start enjoying it more.

"Jack put some tyres on it and there wouldn't be many up pit lane that didn't, so a genuine fifth."

The session was red flagged early for Dale Wood, who speared off at turn one six minutes in.

A mix of co-drivers and primary drivers participated in the session.

While Whincup finished in the top three, his Red Bull teammate Craig Lowndes was further back in the order in 13th.

The #222 Commodore of Nick Percat finished in 25th after suffering from a reported vibration during the session.

Click here for full results.

Qualifying kicks off at 12.20pm local time.