Much of the time certain race was led by Jordan Cox in the Garry Rogers Motorsport Peugeot, who made the most of the reversed top 10 grid to charge clear of debutant Brad Harris (Wall Racing Honda).
Clemente had to wait until the second lap to get past Harris with a smart move to grab second at turn 4.
At the same time Cox survived a hairy moment out front as he slid well wide coming over Lukey Heights.
He did manage to settle into the lead, however came under increasing pressure from Clemente as the race wore on.
The battle then came to a head on the very last lap when Clemente muscled his way past the skittish Peugeot at Southern Loop to set up a maiden TCR Australia race win for both driver and car.
"I'm bloody speechless," Clemente said. "It's been a long time coming. The whole Cupra deal started a long while ago, and to do it now with the family here, on Mothers Day, especially, it's pretty emotional.
"It's been so much hard work. We're a little team punching above our weight. We've had a lot of bad luck, but finally I think it's turning around. And we're ready for it."
Cox came home second ahead while Ben Bargwanna made it two GRM Peugeots on the podium with third.
Harris held on for an impressive fourth from series leader Bailey Sweeny (HMO Hyundai), Aaron Cameron (GRM Peugeot) and Zac Soutar (Team Soutar Motorsport Audi).
Tom Oliphant was eighth in his Lynk & Co ahead of Kody Garland (GRM Peugeot) and race 1 winner Josh Buchan (HMO Hyundai).
The round concludes with a final race at 4:20pm local time.
