"The weekend definitely gives me a bit of confidence heading into a pretty big year for me," said Evans. "It's good to know that I'm still competitive and able to win races against some very tough competition and I'm absolutely rapt."
In race one Evans hooked up well when the lights went out and led the field into turn one from Briton Alex Lynn. The race was red flagged after Bruno Bonifacio mounted the rear of Jann Mardenborough's car to end up high in the air.
At the restart Evans and Lynn were at it hammer and tongs again but the Briton couldn't get past as there was too much debris off the racing line.
"We had a great battle out there but there weren't many places I could safely have a go at overtaking. Mostly I just stayed in Mitch's mirrors and looked for a mistake," said Lynn.
Pipo Derani came home third with Cassidy fourth and Auer fifth, meaning Cassidy extended his lead in the championship to 11 points.
Taking advantage of the reverse top four finishers grid for race two, Cassidy took off like Lance Armstrong on steroids to take his first win of the series and further extend his lead over Auer in the championship.
Derani backed up his race-one result with another podium finish with Auer rounding out the top three, and Lynn came home fifth to settle into third place in the race for the title.
"It was good to get that little monkey [first race win] off my back but even better to get a bit more of a points buffer in the championship over Lucas in the series," said Cassidy.
The series is nicely poised for a major showdown in Manfeild next weekend with any one of five drivers in with a chance to get his name on the TRS trophy. There is also the small matter of the New Zealand Grand Prix title up for grabs - one of only two FIA-recognised GP titles outside Formula One.
In eight years of the championship an overseas driver has yet to leave New Zealand with a TRS title. Defending champion Cassidy sits atop the points table heading to Feilding after extending his lead further after the feature race, but he has four internationals snapping at his heels.
TRS points
After four rounds:
1 Nick Cassidy (New Zealand) 706
2 Lucas Auer (Austria) 674
3 Alex Lynn (UK) 654
4 Steijn Schothorst (Netherlands) 565
5 Felix Serralles (Puerto Rico) 561
6 Bruno Bonifacio (Brazil) 502