SO far, it has been an up-and-down day for the Aussies in the NASCAR Xfinity Series at Portland International Raceway, with Jack Perkins qualifying 12th, while Will Brown will start last after car trouble.

Perkins set the third-fastest time in the first qualifying group, despite suffering an off-track moment, after logging the fourth-best overall time in practice.

For the weekend, the Supercars race winner is leaning on prior knowledge of the circuit, having previously had a troubled run in a Trans Am car at the venue.

Earlier in the year, Perkins made his debut in the Xfinity Series at Chicago, qualifying fifth before being spun out early, which relegated him to a 32nd-place finish in a race won by Shane van Gisbergen.

SVG, however, is not competing this weekend in the Xfinity Series, as the Cup Series is racing on the other side of the country at Darlington.

For the opening race of the Playoffs, van Gisbergen is set to start from 20th.

This week, V8 Sleuth detailed the remarkable histories of Perkins’ two NASCAR Xfinity Series cars, which have their roots in the Cup Series, featuring drivers such as Denny Hamlin and Martin Truex Jr.

Brown, meanwhile, suffered a transmission issue, which caused his car to struggle to shift into second gear. The late change has relegated him to the rear of the grid for the start.

Provisionally, he was 27th in qualifying after being 25th fastest in practice.

This weekend is Brown’s first foray into the Xfinity Series, having previously raced twice in the Cup Series.

On debut at Sonoma last year for Richard Childress Racing, the reigning Supercars champion finished 31st.

This year at Chicago for the RCR-aligned Kaulig Racing, he was the victim of an early pile-up and was classified 39th.

With former full-time driver Josh Williams having parted ways with Kaulig Racing recently, the opportunity opened up for Brown to make a return trip Stateside.

Scoring pole position was Connor Zilisch, returning to action after breaking his collarbone in a victory lane fall suffered at Watkins Glen.

Last week at Daytona, Zilisch took in the green flag before handing the number 88 Chevrolet over to Parker Kligerman, who promptly won, with the victory credited to Zilisch, who now has seven wins for the season to date.

All told, since returning from a back injury at Charlotte in May, the 19-year-old has not finished outside the top five in the 12 races contested.

He has subsequently been named as Shane van Gisbergen’s teammate at Trackhouse Racing in the Cup Series next season.

The 75-lap race is scheduled to start at 9:40am AEST today.