V8 Supercars championship leader Mark Winterbottom has shown he will be a force at the Sandown 500 after producing the quickest practice round of the meet.

Winterbottom surged to the top of the timesheets after the chequered flag went down over Saturday morning’s practice session, overtaking fellow Pepsi Max Ford man Chaz Mostert.

The two Falcons are clearly the cars to beat in the first endurance race of the season, to be fought over 500 kilometres on Sunday afternoon.

Winterbottom, who charted 1:08.8740 around the Melbourne circuit, joined Mostert and Jamie Whincup as the only drivers to crash through the one minute and nine second barrier.

In a highly competitive last practice session before Saturday afternoon qualifying, the top 10 drivers were separated by less than half a second.

Behind the top three are two of the cars to watch: the No.17 Falcon with Scott Pye and comeback-man Marcos Ambrose and the Holden Racing Team No.22 with Russell Ingall deputising as co-driver for the injured James Courtney.

Dale Wood endured a challenging session, taking a long trip off the circuit at the challenging turn one, only to stop centimetres before the tyre wall.

A three-stage qualifying process was scheduled to begin at 12:20 AEST.

After an initial grid is set in the first session, two qualifying races will set the grid for Sunday’s grand race.