Early boost for Whincup

Last year's Sandown champ has led the way in the crucial first practice session at this week's Wilson Security Sandown 500.

Jamie Whincup topped the timesheets with a 1min09.5169, his Holden holding off the Falcons in the 30-minute dash.

The session is critical to progress in practice today, given it is the only opportunity for the primary driver to get behind the wheel.

Two 30-minute sessions remain for co-drivers only - which will give co-driver Paul Dumbrell good seat time ahead of tomorrow's qualifying race.

Whincup and Dumbrell did not benefit from the Red Bull team's test day prior to the enduros because the #1 Commodore suffered from a vibration that kept it sidelined for much of the day.

However, engineer Mark Dutton was confident the issue would be resolved - and Whincup bounced back to prove it this morning.

Whincup held off the promising Prodrive Falcons, with Chaz Mostert home second and Championship leader Mark Winterbottom third.

It was an impressive effort by Scott Pye, who came home fifth after leading the session at a time. Plenty of eyes will be on the XBOX coloured DJR Team Penske Falcon this weekend, with Marcos Ambrose back as a co-driver.

"I was really disappointed there, we were up a couple of tenths and I sort of threw it away at the end there... nice to be disappointed with top five," Pye said, getting out of the car.

"Every time we come out we're getting stronger and moving forward. Looking forward to getting Marcos in the car his afternoon."

David Reynolds came home fourth, meaning FG X Falcons held four of the top five positions.

Jack Perkins, in the Holden Racing Team #22 came home 13th, and Craig Lowndes was back in 23rd.

Click here for full results.

The co-drivers hit the track at 12.30pm local time for practice two.