Matthew Brabham and Nathan Herne have impressed in the final round of the American Trans Am Series at the Circuit of the Americas.

The third-generation Brabham topped the timesheets for the Trans Am class in practice in the #20 CD Racing Ford Mustang, qualifying second with a 2:04.362s, before going onto finish the 30-lap race in the same position.

Brabham, who finished third in this year’s Indy Lights Series, coupled his campaign with several outings in the American Trans Am Series, picking up two victories from three races.

In 2021, the 28-year-old finished first in his only American Trans Am Series race of the season, also at COTA.

Brabham was not the only Australian racing at the Texas circuit, with Herne finishing fourth in the TA2 class in a field of over 50 cars.

Piloting the #29 Stevens-Miller Racing Ford Mustang, Herne qualified 12th for the one-hour race and made strong early progress to be in contention for a podium finish.

The two-time Australian Trans Am title winner was battling for third place, only to make contact with his rival, damaging the front splitter, and losing vital downforce.

“Had the pace to win at the end there but punched a hole through the front end and lost a heap of front aero,” Herne explained.

“Add into the mix a bunch of oil on track and I was hanging on.

“All in all an awesome trip. P4 out of 55 cars is a pretty good result considering. Just got knocked off on the last lap for P3.

“We were ridiculously fast so it’s one of those cases of missed opportunities, quite a big lesson to learn as I still haven’t had a chance to show what I’m capable of over here, we were still consistently in the top 10, so I guess that’s something to be happy with.

“Thanks to everyone for making it all possible, enjoyed every minute of it.”

Herne will return to Australia this week to compete in the National Trans Am Series at the Supercheap Auto Bathurst International over the weekend.