He and his car were fast straight out of the box and proceeded to romp away with the first win of the 15-race series.
Defending champion Cassidy is with a new team this year, having moved from Giles Motorsport to M2 Competition and was feeling his way in the new environment.
However, again experience in Europe came to his aid, and he followed Auer home in race one with Alex Lynn in third.
Brazilian newcomer Pipo Derani took advantage of being on pole for the reverse top six grid in Sunday morning's race and held off the pack to take the win from Felix Serralles and Lynn after Bruno Bonifacio was pinged with a time penalty.
Of the Kiwi drivers, Cassidy was again the best, finishing fourth, with local Southland lad Damon Leitch eighth and Formula Ford graduate Michael Scott 16th.
The feature race on Sunday afternoon opened spectacularly when Brit Lynn and Serralles had a coming together causing Lynn to fire of the track. He headed into the tyre barrier and launched into the air, the car eventually landing back on its wheels.
Lynn was able to exit the car unaided, albeit very shaken.
On the restart Serralles put his near-disaster behind him and drove away from the field to take his first win of the weekend from Auer and young Steijn Schothorst from the Netherlands.
With maximum points from the last race coupled with his previous second and fourth places, Serralles leads the championship heading to round two next weekend at Timaru. Auer lies second with Derani third and Cassidy hovering just behind in fourth. Fellow Kiwis Leitch and Scott are eighth and 16th respectively.
It was also the opening round of the NZV8 championship, with three of the new generation cars in the field. Former V8 Supercars driver Jason Bargwanna suffered mechanical dramas with his new car in race one, allowing Martin Short, driving a new Toyota Camry V8, to become the first driver to win an NZV8 race in something other than a Holden or a Ford.
Bargwanna was at his best in his new-generation Holden in Sunday's two races, romping away in both. He was particularly good in the last race after starting from the bag of the grid around 30 seconds after the old cars took off.
Within half a dozen laps he was in the lead but had to pit so went to rear of the field. Only the new-generation cars had to pit so Bargwanna proceeded to monster the field again and regained the lead with a lap to go. Short managed to unwind himself in the Toyota to take second place. Bargwanna leads the NZV8 TLX championship by one point from Short.
AJ Lauder leads the NZV8s TL championship from another newcomer to the category, Shaun Varney, and local driver Grant Molloy.
Close racing in Formula Ford produced three different winners, Christchurch drivers James Munro and Michael Collins, and local man Brendon Leitch. Collins and Leitch are tied for the lead in the championship.
