Stone Brothers Racing's Marcos Ambrose has started his last weekend of V8 Supercar competition in impressive fashion by setting the second-fastest time in the opening practice for this weekend's BigPond Grand Finale at Phillip Island.

Ambrose, the two-time and defending series champion, was just a fraction of a second behind fellow Ford driver Jason Bright, who uses the fast and flowing Victorian venue as his regular test track.

Ambrose is having his last race in the Pirtek Falcon this weekend before heading to the US next month in preparation for his entry into the Craftsman Trucks NASCAR Series.

Ambrose's SBR teammate Russell Ingall was 10th in the two-hour session after bolting on a fresher set of tyres on his Caltex Falcon with about six minutes remaining in the run.

Ingall currently leads this year's championship by 49 points from fellow Ford driver Craig Lowndes. Ambrose is another 37 points back in third.

Ingall needs to ensure that he remains within eight spots of Lowndes in the weekend's three races to clinch his first title.

There will be qualifying, a top 10 shootout and a 23-lap race tomorrow. There will be a pair of 32-lap races on Sunday.


"At the end of the day it was tyres that made the difference today," said Ambrose.

"We had a pretty quick car and I probably could have gone a little faster, but I came in on my fastest lap because we still had a few things to change and we were running out of laps.

"We thought we might struggle for aero and mechanical grip around here, but we seem to be in pretty good shape.

"We just needed to put ourselves in the best possible position for tomorrow and I think we have sorted plenty of things out today.

"The brake problem we have had the last couple of rounds has been solved, although this place is not as tough on brakes as either Indy or Symmons Plains.

"I just need to fight like a dog and hang on and be in a position to capitalise if Russell (Ingall) has a problem.

"I have mixed emotions about this weekend because I have made a lot of friends up and down pit lane.

"On the other hand I am heading off the US with another great challenge in front of me.

"As for the championship, I feel like I have just finished my school exams. I have done the work and I am now just waiting for the results."

"It was important for us to be in the top half of the field for tomorrow's qualifying," said Ingall.

"We put a good set of tyres on at the end and that jumped us into the top 10.

"We have been working on race set-up and I feel really comfortable in the Caltex Falcon.

"I just need to make sure I hang in there.

"Marcos and (Craig) Lowndes seem to be going pretty good, so I might just sit back and watch them swap paint.

"Our brake problems from the last couple of rounds seem to be sorted, which helps in the confidence department.

"It was actually quite hot out there today, probably one of the hottest days we have had here. There weather is always unpredictable at Phillip Island and is sure to be a big variable again this weekend."